SharePoint 2010 File Name, Length, Size and Invalid Character Restrictions and Recommendations

While some things haven’t changed much, I felt it was important to revisit these classic file and folder restrictions. Today I was looking at my blog post from 2008 on file names, lengths, size and so on and noticed it was the most popular post on my old blog. I haven’t revisited that topic in a long time. I’ve updated it here, and added some additional recommendations.

Site, Folder and File name restrictions

KB Article 905231 I’ve added some additional symbols and recommendations.

  • Site Names
    • Not Allowed: | # { } % & <TAB>" ~ + / : * ? " < >
    • Avoid starting sites with an underscore (_) or with the period character.
    • Site names can cause confusion and corruption if they have periods, apostrophes or commas
    • They should not have consecutive periods or end with a period.
      • You cannot use the period character at the end of a site name
    • Many other symbols are not recommended such as $^()-_=+[]`! (other international currency symbols and international symbols should be avoided in site names, but some are more acceptable in file names. Ascii is preferred when possible.
  • Folder Names and File Names
    • Do not use: " # % & * : < > ? / { | } ~
    • File names cannot be longer than 128 characters
    • Do not use the period character consecutively in the middle of a file name.  For example, "" is invalid.
    • You cannot use the period character at the end of a file name
    • You cannot start a file name with the period character
    • Many other symbols are not recommended such as $^()-_=+[]`! (other international currency symbols and international symbols should be avoided in site names, but some are more acceptable in file names. Ascii is preferred when possible.
  • In addition, file names and folder names may not end with: (Many of these are international symbols)
    • .files, _files , -Dateien , _fichiers , _bestanden , _file ,_archivos ,-filer,_tiedostot ,_pliki ,_soubory ,_elemei ,

                   _arquivos ,_dosyalar ,_datoteke ,_fitxers,_failid 

                  ,_fails ,_bylos ,_fajlovi,_fitxategiak

Examples of Legal File Names

  • AllItems.docx
  • Dept_1234.doc
  • Long.Name.With.Dots.txt

Examples of Illegal Site Names

  • Intranet/sites/People & Process
  • Intranet/sites/My Math is 10% Here
  • Intranet/sites/_foobar
  • Intranet/sites/#FAIL
  • Intranet/sites/Jimmy+Bean


Examples of illegal file names:

  • HailCæsar.wav.
  • Wow…BadStuff.txt
  • 揵.htm
  • Roger&Hamerstein.mp3
  • WhatsUp?.doc

Note that word may let you save this, but uploading it to SharePoint will be your challenge. Sometimes you’re even allowed to upload it through the explorer view, and it will block you from the web interface.


File and Folder name lengths

  • Link list items are restricted to 256 characters and will truncate links to SharePoint documents (or anything else) with lengths longer than this.
  • When storing files the structure and files (entire path including sites, folders, and file name) cannot add up to more than 260 characters or they will see an error message or form validation error with the explanation around the URL length. 


When using multi file upload interface: Make sure the total size of all your files is not greater than the upload limit set for your web application. 


File Size Maximums

Max File Size Default: 50MB Maximum setting: 2GB (per file)

List data: Max of 8kb of data

100 MB is what I recommend for most typical environments as a great compromise, but don’t recommend more than 500MB for most environments without External or Remote Blob storage.

(If you set it to 0 or 2047 MB, it will be the same as 2GB file.) Realistically a few hundred MB is really all you can get, unless you have fast LAN access. Even with LAN access there are cases where upload can fail… Out of memory errors in SQL, Out of memory on web front end, and various places where timeouts may occur. Server admins see the appendix.

NOTE: I understand that even if you use RBS or Remote Blob Storage and most third parties, you still can’t support files over 2GB, but you’ll have to check with your vendor.



I have heard of people who have had the issue of URLScan applied to the web server. It has a default limit of 30mb set in its .ini file. Once that file size is hit it was just dropping the transfer



As well there are other things that you can find that will block your files:

Each Web Application contains a list of blocked file types that is based on file name extensions. For example, you can block files that have the .exe extension. By default, many file types are blocked, including file types that are treated as executable by Internet Explorer. Files, whose names include braces, (for example, filename.{doc}) are also blocked by default.


Blocked File Type Reference (The Outlook 2010 blocked file resource file list is a great reference, and for understanding the files is actually even better than the default SharePoint Blocked File List)

Here are a few file types I typically remove from the blocked file list below: URL, LNK, CHM, HLP

I often add .MP3, PST, OST, and sometimes MP4. Some will add .ZIP, but I recommend allowing the .zip, arj, rar, etc… file as a common mechanism for transporting larger files.


File extension

File type


Microsoft Access project extension


Microsoft Access project


Application file


Active server page


Microsoft Visual Basic class module


Batch file


Internet Security Certificate file


Compiled HTML Help file


DOS command file, Microsoft Windows NT command script


Windows Help contents file


Microsoft MS_DOS program


Control Panel extension


Security certificate


Script file


DER Encoded X509 certificate file


Executable file


Microsoft Visual FoxPro compiled program


Windows Gadget


Windows program group file


Help file


Help project file


HTML program


Information or setup file


Internet Naming Service


Internet Communication settings


Internet Document Set file


JAVA archive file


JavaScript source code


JScript Encoded script file


UNIX Shell script file


Windows shortcut


Microsoft Access module shortcut


Microsoft Access shortcut


Microsoft Access diagram shortcut


Microsoft Access macro shortcut


Microsoft Access query shortcut


Microsoft Access report shortcut


Microsoft Access stored procedures


Microsoft Access table shortcut


Media attachment unit


Microsoft Access view shortcut


Microsoft Access data access page


Manifest configuration file


Microsoft Access add-in program


Microsoft Access program


Microsoft Access MDE database file


Microsoft Access data file


Microsoft Access workgroup


Microsoft Access wizard program


Microsoft Common Console document


Windows PowerShell script helper


Windows PowerShell script helper


Windows PowerShell script helper


Windows PowerShell script helper


Windows PowerShell script helper


Windows PowerShell script helper


Windows Installer package


Windows Installer update package file


Visual Test source file


Microsoft Office profile settings file


Open software description file


Microsoft Visual Test compiled script


Windows program information file


Perl script file


Developer Studio build log


Outlook profile file


Program source file


Windows PowerShell


Windows PowerShell


Windows PowerShell


Windows PowerShell


Windows PowerShell


Windows PowerShell


Microsoft Outlook personal folder file


Registration entries, Registry data file


Windows Explorer command file


Windows screen saver


Windows script component


Windows shortcut to a document


Shell Scrap object file


Temporary file or folder


Uniform Resource Locator (Internet shortcut)


Microsoft Visual Basic Scripting Edition (VBScript) file


VBScript Encoded script file


Visual Basic project file


VBScript script file, Visual Basic for Applications script file


Microsoft Visual Studio .NET binary-based macro project file


Microsoft Visio workspace file


Windows script file


Windows script component


Windows script file


Windows Script Host settings file


XAML browser application


Microsoft Exchange public folder shortcut


To set the upload size to 200 megabytes, use the following syntax:

stsadm -o setproperty -pn max-file-post-size -pv 200

To view the current setting of the maximum file post size property, use the following syntax:

stsadm -o getproperty -pn max-file-post-size –url http://server_name


For Admins you’ll need to make sure you increase your timeouts and settings:

IIS Connection Timeouts

  • Tune the Microsoft Internet Information Services (IIS) connection timeout setting.

The default timeout for connections in IIS is 120 seconds (2 minutes). Depending on your maximum file size and how long it takes for the file to be uploaded, you may not need to change this setting. If, however, IIS is timing out when you upload large files, you can change this property to ensure that larger files can be uploaded successfully.

    1. Click Start, point to All Programs, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.
    2. Right-click the virtual server you want to configure, and then click Properties.
    3. Click the Web Site tab.
    4. In the Connections section, in the Connection timeout box, type the number of seconds you want IIS to wait before timing out.
    5. Click OK.


For Admins you can modify:

  • Central Admin – Security – Define blocked file typesWeb Application menu, click Change Web Application. Add blocked file extensions you want to block or remove those you want to remove.

 There are some settings for increasing your maximum timeout values including


ExecutionTimeout value to web config in the layouts folder and the virtualDirectoryFolder:


layouts dir

Existing code

 <location path="upload.aspx">


      <httpRuntime maxRequestLength="2097151" />




Replacement code

 <location path="upload.aspx">


      <httpRuntime executionTimeout="999999" maxRequestLength="2097151" />




virtualDirectoryFolder dir

Existing line

<httpRuntime maxRequestLength="51200" />

Replacement line

<httpRuntime executionTimeout="999999" maxRequestLength="51200" />



Default chunk size for large files:

Sharepoint default chunk size is set to 5MB, this means that if a client tries to open a document of 50MB and the chunk size is 5MB, the document is divided and retrieved in 10 chunks. Each chunk will be loaded into the memory of both the WFE handling the request and the SQL Server. Note I looked for a powershell setting and couldn’t find a reference in the 10 minutes I looked for you J By the way… don’t use smiley’s in your file names either J


stsadm -o setproperty -pn large-file-chunk-size -pv 1073741824

(Note: Requires IISReset) 







2 Comments on “SharePoint 2010 File Name, Length, Size and Invalid Character Restrictions and Recommendations

  1. I suggest you try Long path tool is the very good program for easily delete, copy & rename long path files, error, unlock solution.
    Try it and solve your problem.
    I used long path tool and I solve my error, unlock problem solution.

  2. Microsoft file path limitations may limit a path name to 260. We can use Long Path Tool to fix it

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