Windows max file length

In Windows 10, you can enable long file name support, which allows file names up to 32,767 characters (although you lose a few characters for mandatory characters that are part of the name). To enable this, perform the following: Start the registry editor (regedit.exe)

1. What is the maximum length of a filename?
2. How do I allow long file names in Windows 10?
3. What is the character limit for file names in Windows?
4. What is the maximum length of the filename in due?
5. Why is there a 255 character limit?
6. When did Windows allow long file names?
7. Why does Windows have a 260 character limit?
8. How long should file names be?
9. Can a file path be too long?
10. How many words is 255 characters?
11. Is the maximum length of the filename is MS DOS?
12. What is the maximum length of the filename in DOS a 4?
13. How long can a file path be?

What is the maximum length of a filename?

The maximum combined length of the file name and path name is 1024 characters. The Unicode representation of a character can occupy several bytes, so the maximum number of characters that a file name might contain can vary. On Linux: The maximum length for a file name is 255 bytes.

How do I allow long file names in Windows 10?

Navigate to Local Computer Policy > Computer Configuration > Administrative Templates > System > Filesystem. Double click Enable NTFS long paths. Select Enabled, then click OK.

What is the character limit for file names in Windows?

Microsoft Windows has a MAX_PATH limit of ~256 characters. If the length of the path and filename combined exceed ~256 characters you will be able to see the path/files via the Windows Explorer, but may not be able to delete/move/rename these paths/files.

What is the maximum length of the filename in due?

Why is there a 255 character limit?

The limit occurs due to an optimization technique where smaller strings are stored with the first byte holding the length of the string. Since a byte can only hold 256 different values, the maximum string length would be 255 since the first byte was reserved for storing the length.

When did Windows allow long file names?

Windows finally added long file name support in Windows 95, joining other operating systems like Unix, OS/2, and macOS that already included long file name support. Released in August 1995, Windows 95 featured a new version of FAT, called VFAT, that supported file names with a maximum length of 255 characters.

Why does Windows have a 260 character limit?

It’s just that the property of a folder in Windows only reports the number of folder and files that don’t violate the limitation. It’s as if that Windows Explorer doesn’t dig any deeper to discover folders when the max path is reached. It is possible to delete a long path in 7-zip with shift-del.

How long should file names be?

Be unique and consistently structured; Be persistent and not tied to anything that changes over time or location; Limit the character length to no more than 25-35 characters; Use leading 0s to facilitate sorting in numerical order if following a numeric scheme “001, 002, …

Can a file path be too long?

Most standard applications, including Windows Explorer (File Explorer), do not work correctly with long path files exceeding 256 characters. Under the file name, Windows understands the entire path, starting with the root of the drive, ending with the last subfolder, and the file name itself.

How many words is 255 characters?

Answer: 250 characters is between 40 words and 60 words with spaces included in the character count. If spaces are not included in the character count, then 250 characters is between 40 words and 80 words.

Is the maximum length of the filename is MS DOS?

For example, the older MS-DOS FAT file system supports a maximum of 8 characters for the base file name and 3 characters for the extension, for a total of 12 characters including the dot separator. This is commonly known as an 8.3 file name.

What is the maximum length of the filename in DOS a 4?

How long can a file path be?

While Windows’ standard file system (NTFS) supports paths up to 65,535 characters, Windows imposes a maximum path length of 255 characters (without drive letter), the value of the constant MAX_PATH. This limitation is a remnant of MS DOS and has been kept for reasons of compatibility.

A filename or file name is a name used to uniquely identify a computer file in a file system. Different file systems impose different restrictions on filename lengths.

A filename may (depending on the file system) include:

• name – base name of the file
• extension – may indicate the format of the file (e.g. .txt for plain text, .pdf for Portable Document Format, .dat for unspecified binary data, etc.)

The components required to identify a file by utilities and applications varies across operating systems, as does the syntax and format for a valid filename.

The characters allowed in filenames depend on the file system. The letters A–Z and digits 0–9 are allowed by most file systems; many file systems support additional characters, such as the letters a–z, special characters, and other printable characters such as accented letters, symbols in non-Roman alphabets, and symbols in non-alphabetic scripts. Some file systems allow even unprintable characters, including Bell, Null, Return and Linefeed, to be part of a filename,^[1] although most utilities do not handle them well.

Filenames may include things like a revision or generation number of the file,
a numerical sequence number (widely used by digital cameras through the DCF standard),
a date and time (widely used by smartphone camera software and for screenshots),
or a comment such as the name of a subject or a location or any other text to help identify the file.

Some people use the term filename when referring to a complete specification of device, subdirectories and filename such as the Windows C:\Program Files\Microsoft Games\Chess\Chess.exe.
The filename in this case is Chess.exe.
Some utilities have settings to suppress the extension as with MS Windows Explorer.^{[not verified in body]}

During the 1970s, some mainframe and minicomputers had operating systems where files on the system were identified by a user name, or account number.

For example, on the TOPS-10 and RSTS/E operating systems from Digital Equipment Corporation, files were identified by

• optional device name (one or two characters) followed by an optional unit number, and a colon «:». If not present, it was presumed to be SY:
• the account number, consisting of a bracket «[«, a pair of numbers separated by a comma, and followed by a close bracket «]». If omitted, it was presumed to be yours.
• mandatory file name, consisting of 1 to 6 characters (upper-case letters or digits)
• optional 3-character extension.

On the OS/360 and successor operating systems from IBM, a file name can be up to 44 characters, consisting of upper case letters, digits, and the period; a file name had to start with a letter or number, a period must occur at least once each 8 characters, two consecutive periods can not appear in the name, and the name must end with a letter or digit.^[2][3] By convention, when using TSO, the letters and numbers before the first period is the account number of the owner or the project it belongs to, but there is no requirement to use this convention.^[4]

On the McGill University MUSIC/SP system, file names consisted of

• Optional account number, which was one to four characters followed by a colon.If the account number was missing, it was presumed to be in your account, but if it was not, it was presumed to be in the *COM: pseudo-account, which is where all files marked as public were catalogued.
• 1–17 character file name, which could be upper case letters or digits, and the period, with the requirement it not begin or end with a period, or have two consecutive periods.

The Univac VS/9 operating system had file names consisting of

• Account name, consisting of a dollar sign «$», a 1-7 character (letter or digit) username, and a period («.»). If not present it was presumed to be in your account, but if it was not, the operating system would look in the system manager’s account $TSOS. If you typed in a dollar sign only as the account, this would indicate the file was in the $TSOS account unless the first 1–7 character of the file name before the first period matched an actual account name, then that account was used, e.g. ABLE.BAKER is a file in your account, but if not there the system would search for $TSOS.ABLE.BAKER, but if $ABLE.BAKER was specified, the file $TSOS.ABLE.BAKER would be used unless $ABLE was a valid account, then it would look for a file named BAKER in that account.
• File name, 1–56 characters (letters and digits) separated by periods. File names cannot start or end with a period, nor can two consecutive periods appear.

In 1985, RFC 959 officially defined a pathname to be the character string that must be entered into a file system by a user in order to identify a file.^[5]

On early personal computers using the CP/M operating system, filenames were always 11 characters. This was referred to as the 8.3 filename with a maximum of an 8 byte name and a maximum of a 3 byte extension. Utilities and applications allowed users to specify filenames without trailing spaces and include a dot before the extension. The dot was not actually stored in the directory. Using only 7 bit characters allowed several file attributes to be included in the actual filename by using the high-order-bit; these attributes included Readonly, Archive, and System.^[6] Eventually this was too restrictive and the number of characters allowed increased. The attribute bits were moved to a special block of the file including additional information.^{[citation needed]}

The original File Allocation Table (FAT) file system, used by Standalone Disk BASIC-80, had a 6.3 file name, with a maximum of 6 bytes in the name and a maximum of 3 bytes in the extension. The FAT12 and FAT16 file systems in IBM PC DOS/MS-DOS and Microsoft Windows prior to Windows 95 used the same 8.3 convention as the CP/M file system. The FAT file systems supported 8-bit characters, allowing them to support non-ASCII characters in file names, and stored the attributes separately from the file name.

Around 1995, VFAT, an extension to the MS-DOS FAT filesystem, was introduced in Windows 95 and Windows NT. It allowed mixed-case long filenames (LFNs), using Unicode characters, in addition to classic «8.3» names.

Programs and devices may automatically assign names to files such as a numerical counter (for example IMG_0001.JPG) or a time stamp with the current date and time.

The benefit of a time stamped file name is that it facilitates searching files by date, given that file managers usually feature file searching by name. In addition, files from different devices can be merged in one folder without file naming conflicts.

Numbered file names, on the other hand, do not require that the device has a correctly set internal clock. For example, some digital camera users might not bother setting the clock of their camera. Internet-connected devices such as smartphones may synchronize their clock from a NTP server.

An absolute reference includes all directory levels. In some systems, a filename reference that does not include the complete directory path defaults to the current working directory. This is a relative reference. One advantage of using a relative reference in program configuration files or scripts is that different instances of the script or program can use different files.

This makes an absolute or relative path composed of a sequence of filenames.

Unix-like file systems allow a file to have more than one name; in traditional Unix-style file systems, the names are hard links to the file’s inode or equivalent. Windows supports hard links on NTFS file systems, and provides the command fsutil in Windows XP, and mklink in later versions, for creating them.^[7][8] Hard links are different from Windows shortcuts, classic Mac OS/macOS aliases, or symbolic links. The introduction of LFNs with VFAT allowed filename aliases. For example, longfi~1.??? with a maximum of eight plus three characters was a filename alias of «long file name.???» as a way to conform to 8.3 limitations for older programs.

This property was used by the move command algorithm that first creates a second filename and then only removes the first filename.

Other filesystems, by design, provide only one filename per file, which guarantees that alteration of one filename’s file does not alter the other filename’s file.

Some filesystems restrict the length of filenames. In some cases, these lengths apply to the entire file name, as in 44 characters in IBM z/OS.^[3] In other cases, the length limits may apply to particular portions of the filename, such as the name of a file in a directory, or a directory name. For example, 9 (e.g., 8-bit FAT in Standalone Disk BASIC), 11 (e.g. FAT12, FAT16, FAT32 in DOS), 14 (e.g. early Unix), 21 (Human68K), 31, 30 (e.g. Apple DOS 3.2 and 3.3), 15 (e.g. Apple ProDOS), 44 (e.g. IBM S/370),^[3] or 255 (e.g. early Berkeley Unix) characters or bytes. Length limits often result from assigning fixed space in a filesystem to storing components of names, so increasing limits often requires an incompatible change, as well as reserving more space.

A particular issue with filesystems that store information in nested directories is that it may be possible to create a file with a complete pathname that exceeds implementation limits, since length checking may apply only to individual parts of the name rather than the entire name. Many Windows applications are limited to a MAX_PATH value of 260, but Windows file names can easily exceed this limit.^[9] From Windows 10, version 1607, MAX_PATH limitations have been removed.^[10]

Filenames in some file systems, such as FAT and the ODS-1 and ODS-2 levels of Files-11, are composed of two parts: a base name or stem and an extension or suffix used by some applications to indicate the file type. Some other file systems, such as Unix file systems, VFAT, and NTFS, treat a filename as a single string; a convention often used on those file systems is to treat the characters following the last period in the filename, in a filename containing periods, as the extension part of the filename.

Multiple output files created by an application may use the same basename and various extensions. For example, a Fortran compiler might use the extension FOR for source input file, OBJ for the object output and LST for the listing. Although there are some common extensions, they are arbitrary and a different application might use REL and RPT. Extensions have been restricted, at least historically on some systems, to a length of 3 characters, but in general can have any length, e.g., html.

There is no general encoding standard for filenames.

File names have to be exchanged between software environments for network file transfer, file system storage, backup and file synchronization software, configuration management, data compression and archiving, etc. It is thus very important not to lose file name information between applications. This led to wide adoption of Unicode as a standard for encoding file names, although legacy software might not be Unicode-aware.

Traditionally, filenames allowed any character in their filenames as long as they were file system safe.^[11] Although this permitted the use of any encoding, and thus allowed the representation of any local text on any local system, it caused many interoperability issues.

A filename could be stored using different byte strings in distinct systems within a single country, such as if one used Japanese Shift JIS encoding and another Japanese EUC encoding. Conversion was not possible as most systems did not expose a description of the encoding used for a filename as part of the extended file information. This forced costly filename encoding guessing with each file access.^[11]

A solution was to adopt Unicode as the encoding for filenames.

In the classic Mac OS, however, encoding of the filename was stored with the filename attributes.^[11]

The Unicode standard solves the encoding determination issue.

Nonetheless, some limited interoperability issues remain, such as normalization (equivalence), or the Unicode version in use. For instance, UDF is limited to Unicode 2.0; macOS’s HFS+ file system applies NFD Unicode normalization and is optionally case-sensitive (case-insensitive by default.) Filename maximum length is not standard and might depend on the code unit size. Although it is a serious issue, in most cases this is a limited one.^[11]

On Linux, this means the filename is not enough to open a file: additionally, the exact byte representation of the filename on the storage device is needed. This can be solved at the application level, with some tricky normalization calls.^[12]

The issue of Unicode equivalence is known as «normalized-name collision». A solution is the Non-normalizing Unicode Composition Awareness used in the Subversion and Apache technical communities.^[13] This solution does not normalize paths in the repository. Paths are only normalized for the purpose of comparisons. Nonetheless, some communities have patented this strategy, forbidding its use by other communities.^{[clarification needed]}

To limit interoperability issues, some ideas described by Sun are to:

• use one Unicode encoding (such as UTF-8)
• do transparent code conversions on filenames
• store no normalized filenames
• check for canonical equivalence among filenames, to avoid two canonically equivalent filenames in the same directory.^[11]

Those considerations create a limitation not allowing a switch to a future encoding different from UTF-8.

One issue was migration to Unicode.
For this purpose, several software companies provided software for migrating filenames to the new Unicode encoding.

• Microsoft provided migration transparent for the user throughout the VFAT technology
• Apple provided «File Name Encoding Repair Utility v1.0».^[14]
• The Linux community provided «convmv».^[15]

Mac OS X 10.3 marked Apple’s adoption of Unicode 3.2 character decomposition, superseding the Unicode 2.1 decomposition used previously. This change caused problems for developers writing software for Mac OS X.^[16]

Within a single directory, filenames must be unique. Since the filename syntax also applies for directories, it is not possible to create a file and directory entries with the same name in a single directory. Multiple files in different directories may have the same name.

Uniqueness approach may differ both on the case sensitivity and on the Unicode normalization form such as NFC, NFD.
This means two separate files might be created with the same text filename and a different byte implementation of the filename, such as L»\x00C0.txt» (UTF-16, NFC) (Latin capital A with grave) and L»\x0041\x0300.txt» (UTF-16, NFD) (Latin capital A, grave combining).^[17]

Some filesystems, such as FAT prior to the introduction of VFAT, store filenames as upper-case regardless of the letter case used to create them. For example, a file created with the name «MyName.Txt» or «myname.txt» would be stored with the filename «MYNAME.TXT» (VFAT preserves the letter case). Any variation of upper and lower case can be used to refer to the same file. These kinds of file systems are called case-insensitive and are not case-preserving. Some filesystems prohibit the use of lower case letters in filenames altogether.

Some file systems store filenames in the form that they were originally created; these are referred to as case-retentive or case-preserving. Such a file system can be case-sensitive or case-insensitive. If case-sensitive, then «MyName.Txt» and «myname.txt» may refer to two different files in the same directory, and each file must be referenced by the exact capitalization by which it is named. On a case-insensitive, case-preserving file system, on the other hand, only one of «MyName.Txt», «myname.txt» and «Myname.TXT» can be the name of a file in a given directory at a given time, and a file with one of these names can be referenced by any capitalization of the name.

From its original inception, the file systems on Unix and its derivative systems were case-sensitive and case-preserving. However, not all file systems on those systems are case-sensitive; by default, HFS+ and APFS in macOS are case-insensitive but case-preserving, and SMB servers usually provide case-insensitive behavior (even when the underlying file system is case-sensitive, e.g. Samba on most Unix-like systems), and SMB client file systems provide case-insensitive behavior. File system case sensitivity is a considerable challenge for software such as Samba and Wine, which must interoperate efficiently with both systems that treat uppercase and lowercase files as different and with systems that treat them the same.^[18]

File systems have not always provided the same character set for composing a filename. Before Unicode became a de facto standard, file systems mostly used a locale-dependent character set. By contrast, some new systems permit a filename to be composed of almost any character of the Unicode repertoire, and even some non-Unicode byte sequences. Limitations may be imposed by the file system, operating system, application, or requirements for interoperability with other systems.

Many file system utilities prohibit control characters from appearing in filenames. In Unix-like file systems, the null character^[19] and the path separator / are prohibited.

File system utilities and naming conventions on various systems prohibit particular characters from appearing in filenames or make them problematic:^[9] Except as otherwise stated, the symbols in the Character column, « and < for example, cannot be used in Windows filenames.

Note 1: While they are allowed in Unix file and folder names, most Unix shells require specific characters such as spaces, <, >, |, \, and sometimes :, (, ), &, ;, #, as well as wildcards such as ? and *, to be quoted or escaped:

five\ and\ six\<seven (example of escaping)
'five and six<seven' or "five and six<seven" (examples of quoting)

The character å (0xE5) was not allowed as the first letter in a filename under 86-DOS and MS-DOS/PC DOS 1.x-2.x, but can be used in later versions.

In Windows utilities, the space and the period are not allowed as the final character of a filename.^[20] The period is allowed as the first character, but some Windows applications, such as Windows Explorer, forbid creating or renaming such files (despite this convention being used in Unix-like systems to describe hidden files and directories). Workarounds include appending a dot when renaming the file (that is then automatically removed afterwards), using alternative file managers, creating the file using the command line, or saving a file with the desired filename from within an application.^[21]

Some file systems on a given operating system (especially file systems originally implemented on other operating systems), and particular applications on that operating system, may apply further restrictions and interpretations. See comparison of file systems for more details on restrictions.

In Unix-like systems, DOS, and Windows, the filenames «.» and «..» have special meanings (current and parent directory respectively). Windows 95/98/ME also uses names like «…», «….» and so on to denote grandparent or great-grandparent directories.^[22] All Windows versions forbid creation of filenames that consist of only dots, although names consisting of three dots («…») or more are legal in Unix.

In addition, in Windows and DOS utilities, some words are also reserved and cannot be used as filenames.^[21] For example, DOS device files:^[23]

CON, CONIN$, CONOUT$, PRN, AUX, CLOCK$, NUL
COM0, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9[9]
LPT0, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9[9]
LST (only in 86-DOS and DOS 1.xx)
KEYBD$, SCREEN$ (only in multitasking MS-DOS 4.0)
$IDLE$ (only in Concurrent DOS 386, Multiuser DOS and DR DOS 5.0 and higher)
CONFIG$ (only in MS-DOS 7.0-8.0)

Systems that have these restrictions cause incompatibilities with some other filesystems. For example, Windows will fail to handle, or raise error reports for, these legal UNIX filenames: aux.c,^[24] q»uote»s.txt, or NUL.txt.

NTFS filenames that are used internally include:

$Mft, $MftMirr, $LogFile, $Volume, $AttrDef, $Bitmap, $Boot, $BadClus, $Secure,
$Upcase, $Extend, $Quota, $ObjId and $Reparse

• File system
• Fully qualified file name
• Long filename
• Path (computing)
• Slug (Web publishing)
• Symbolic link
• Uniform Resource Identifier (URI)
• Uniform Resource Locator (URL) and Internationalized resource identifier
• Windows (Win32) File Naming Conventions (Filesystem Agnostic)

• File Extension Library
• FILExt
• WikiExt — File Extensions Encyclopedia
• «Naming Files, Paths, and Namespaces». Microsoft Docs. December 15, 2022.
• 2009 POSIX portable filename character set
• Standard ECMA-208, December 1994, System-Independent Data Format
• Best Practices for File Naming, USA: Stanford University Libraries, Data Management Services, archived from the original on July 30, 2021

Windows Doesn’t Accept Long Paths by Default

Before Windows 95, Windows only allowed file names that were eight characters long, with a three-character file extension — commonly known as an 8.3 filename. Windows 95 abandoned that to allow long file names, but still limited the maximum path length (which includes the full folder path and the file name) to 260 characters. That limit has been in place ever since. If you’ve ever run into this limit, it was probably when you were trying to copy deep folder structures into other folders, such as when copying the contents of a hard drive to a folder on another drive. The Windows 10 Anniversary Update finally added the option to abandon that maximum path length.

There is one caveat. This new setting won’t necessarily work with every application out there, but it will work with most. Specifically, any modern applications should be fine, as should all 64-bit applications. Older 32-bit applications need to be manifested in order to work, which really just means that the developer has indicated in the application’s manifest file that the application supports longer paths. Most popular 32-bit apps should experience no problem. Still, you don’t risk anything by trying the setting out. If an application doesn’t work, the only thing that will happen is that it won’t be able to open or save files that are saved in places where the full path exceeds 260 characters.

Home Users: Remove the 260 Character Path Limit by Editing the Registry

If you have a Windows Home edition, you will have to edit the Windows Registry to make these changes. You can also do it this way if you have Windows Pro or Enterprise, but feel more comfortable working in the Registry than Group Policy Editor. (If you have Pro or Enterprise, though, we recommend using the easier Group Policy Editor, as described in the next section.)

To get started, open the Registry Editor by hitting Start and typing «regedit.» Press Enter to open Registry Editor and give it permission to make changes to your PC.

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In the Registry Editor, use the left sidebar to navigate to the following key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem

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On the right, find a value named LongPathsEnabled and double-click it. If you don’t see the value listed, you’ll need to create it by right-clicking the FileSystem key, choosing New > DWORD (32-bit) Value, and then naming the new value LongPathsEnabled.

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In the value’s properties window, change the value from 0 to 1 in the «Value data» box and then click OK.

You can now close Registry Editor and restart your computer (or sign out of your account and sign back on). If you ever want to reverse the changes, just head back to the LongPathsEnabled value, and change it from 1 back to 0.

Download Our One-Click Registry Hack

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If you don’t feel like diving into the Registry yourself, we’ve created two downloadable registry hacks you can use. One hack removes the 260-character path limit, and the other hack restores the default limit. Both are included in the following ZIP file. Double-click the one you want to use, click through the prompts, and then restart your computer.

Long Path Names Hacks

These hacks are really just the FileSystem key, stripped down to the LongPathsEnabled value we described above, and then exported to a .REG file. Running the «Remove 260 Character Path Limit» hack sets the LongPathsEnabled value to 1. Running the «Restore 260 Character Path Limit (Default)» hack sets the value back to 0. And if you enjoy fiddling with the Registry, it’s worth taking the time to learn how to make your own Registry hacks.

Pro and Enterprise Users: Remove the 260 Character Path Limit with the Local Group Policy Editor

If you’re using Windows 10 Pro or Enterprise, the easiest way to disable the new app install notifications is by using the Local Group Policy Editor. It’s a pretty powerful tool, so if you’ve never used it before, it’s worth taking some time to learn what it can do. Also, if you’re on a company network, do everyone a favor and check with your admin first. If your work computer is part of a domain, it’s also likely that it’s part of a domain group policy that will supersede the local group policy, anyway.

In Windows 10 Pro or Enterprise, hit Start, type gpedit.msc, and press Enter.

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In the Local Group Policy Editor, in the left-hand pane, drill down to Computer Configuration > Administrative Templates > System > Filesystem. On the right, find the «Enable win32 long paths» item and double-click it.

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Select the «Enabled» option and then click «OK» in the properties window that opens.

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You can now exit the Local Group Policy Editor and restart your computer (or sign out and back in) to allow the changes to take effect. If at any time you want to reverse the changes, just follow the same procedure and set that option back to «Disabled» or «Not Configured.»

The maximum path limit may not be something you’ve ever run into, but for some people, it can certainly be the occasional frustration. Windows 10 has finally added the ability to remove that limit. You just have to make a quick change to the Registry or Group Policy to make it happen.