Invalid file names and file types in onedrive onedrive for business and sharepoint

This article contains information about the restrictions and limitations that apply to file names and file types when syncing with OneDrive for home, OneDrive for work or school or SharePoint in Microsoft 365.

Note: If you're looking for restrictions and limitations that apply to the earlier version of OneDrive (groove.exe), read KB 2933738.

What's new

12 April 2021: Added 50,000 item sharing limits note.

3 March 2021: Maximum file upload size updated to 250 GB.

16 September 2020: Updated info about OneNote notebooks to clarify that the 2GB file size limit applies to SharePoint as well as OneDrive.

31 August 2020: Updated the invalid or blocked file types guidance about .PST files when Known Folder Move is turned on.

28 July 2020: Added note to invalid characters about saving Office files with folder names containing ;

26 June 2020: Added mention of leading and trailing spaces as invalid characters, although this isn't a new limitation.

In this article

Restrictions	Limitations	Troubleshooting tips
Invalid characters	File upload size	OneDrive system requirements
Invalid file or folder names	File name and path lengths	Support and Recovery Assistant
Invalid or blocked file types	Thumbnails and previews	Only sync what you need
Network or mapped drives	Number of items to sync or copy	Syncing too many files
Elevated privileges	Information Rights Management	Duplicate filenames
Sharing	Differential sync
How many OneDrive accounts	Libraries with specific columns
Authenticated proxies	Windows specific limitations
OneNote notebooks	macOS specific limitations

Restrictions

Invalid characters

Applies to: 

Certain characters have special meanings when used in file names in OneDrive, SharePoint, Windows and macOS, such as "*" for wildcards, and "\" in file name paths. If a file or folder you're trying to upload to OneDrive contains any of the characters listed below, it may prevent files and folders from syncing. Rename the file or folder to remove these characters before you upload it.

Characters that aren't allowed in file and folder names  in OneDrive for home, OneDrive for work or school and SharePoint in Microsoft 365	Characters that aren't allowed in file and folder names in OneDrive for work or school on SharePoint Server 2013
" * : < > ? / \ | (Leading and trailing spaces in file or folder names also aren't allowed.)	~ " # % & * : < > ? / \ { | }. (Leading and trailing spaces in file or folder names also aren't allowed.)

Notes: 

• To rename a file or folder in Windows, select it and press F2. To rename a file or folder on a Mac, select it and press the 'return' key. 

• Some organizations don't yet support # and % in names. If you're a global admin or SharePoint admin in Microsoft 365, see Enabling # and % Support on the SharePoint blog to learn how to allow these characters.

• For Office desktop win32 apps: If you're saving an Office file via the Backstage view to a OneDrive or SharePoint folder, you won't be able to save the file if the folder name contains ; (semicolon).

• If you're using Office 2010, you can't use "&" in file and folder names.

• For more information, see When OneDrive renames items with invalid characters and Why has my filename changed from comma to ^J.

Invalid file or folder names

Applies to: 

These names aren't allowed for files or folders: .lock, CON, PRN, AUX, NUL, COM0 - COM9, LPT0 - LPT9, _vti_, desktop.ini, any filename starting with ~$.

Notes: 

• "_vti_" cannot appear anywhere in a file name

• "forms" isn't supported when the folder is at the root level for a library.

• You can't create a folder name in SharePoint that begins with a tilde (~).

Invalid or blocked file types

Applies to:   

Temporary TMP files will not be synced to OneDrive. See OneDrive status stuck on "Sync pending" for more details.

Files that are used by your local computer, such as desktop.ini on Windows or .ds_store on macOS, don't normally sync. If these files do get uploaded to OneDrive during a migration, the sync app will delete the cloud copy and leave the local copy.

Outlook .PST files are supported, however they are synced less frequently compared to other file types to reduce network traffic. To prevent uploading .PST files from the OneDrive sync app, read Blocking syncing of specific file types. To move .PST files out of OneDrive, read How to remove an Outlook PST data file from OneDrive. If users enable PC folder backup (Known Folder Move) manually without the group policy, they will see an error if they have a .PST file in one of their known folders (e.g. Documents). If Known Folder Move is enabled and configured via group policy, .PST files will be migrated.

If you are a OneDrive for work or school user, some file types may be blocked on your organization's SharePoint site. The list of blocked files will vary depending on your administrator.

For security reasons, a number of file names and extensions can't be uploaded since they are executable, used by SharePoint Server, or used by Windows itself. For more info, see Types of files that cannot be added to a list or library.

Network or mapped drives

Applies to: 

You can't add a network or mapped drive as your OneDrive sync location. OneDrive doesn't support syncing using symbolic links or junction points.

Elevated privileges

Applies to: 

OneDrive can't be run with elevated privileges, and you will not be able to see OneDrive menu items within File Explorer. However, the per-machine sync app installation is helpful especially for multi-user computers and when you don't want exe files running from the user profile. See also Unable to share OneDrive files.

Sharing

Applies to: 

You can't share this item because too many items have already been shared in this library

There is a limit of 50,000 items that can be shared within a folder and any sub-folders.

To overcome this restriction, move some items into another folder that is not within the original folder, or choose individual files to share.

Shared with me

You can't synchronize the Shared with me view grouping of files from a OneDrive for work or school site.

Delivery has failed to these recipients or groups error when sharing

You may receive this error message when trying to share to an address that is not associated with a Microsoft account.

How many OneDrive accounts?

Applies to: 

Number of OneDrive accounts

There is a limit to the number of accounts that can be signed in and syncing: each device may only have a maximum of 1 OneDrive for home account and 9 OneDrive for work or school work or school accounts.

OneDrive Guest accounts

Synchronizing content using an external or guest user is currently not supported by OneDrive.

Authenticated proxies

Applies to: 

Authenticated proxies aren't supported in OneDrive.

If you see the error message "Your proxy settings require authentication" or the error code 0x8004de42 when trying to sign in to OneDrive, please check you are not using an authenticated proxy to connect to OneDrive.

OneNote notebooks 

Applies to: 

OneNote notebooks have their own sync mechanism outside of OneDrive. If you plan on sharing a OneNote notebook—with yourself or others—it's best to create it on OneDrive right from the start. Moving an existing OneNote notebook into a folder synced by OneDrive without going through the OneNote application is not currently supported.

Once a OneNote notebook is saved in OneDrive, if you are syncing the folder that contains the notebook, you will find a stub .url file, which will open the notebook on the website.

OneNote notebooks saved in OneDrive or SharePoint are limited to 2GB.

Read how to Move a OneNote notebook to OneDrive.

Limitations

File upload size

Applies to: 

File size limit: 250GB

Note: This applies to an individual file being uploaded or synced, not your total storage. For any file larger than a few GB, we recommend using the OneDrive sync app rather than the website upload feature.

File name and path lengths

Applies to: 

Different apps and Office versions have different limits, and the combination of limitations may be unique to your setup.

The entire decoded file path, including the file name, can't contain more than 400 characters for OneDrive, OneDrive for work or school and SharePoint in Microsoft 365. The limit applies to the combination of the folder path and file name after decoding. 

• For example, if the file URL in SharePoint is https://www.contoso.com/sites/marketing/documents/Shared%20Documents/Promotion/Some%20File.xlsx, the limit applies to "sites/marketing/documents/Shared Documents/Promotion/Some File.xlsx."

• Likewise, if the file URL in OneDrive is https://contoso-my.sharepoint.com/personal/meganb_contoso%20_com/_layouts/15/onedrive.aspx?id=%2Fpersonal%2Fmeganb%5Fcontoso%5Fcom%2FDocuments%2FContracts%2FVendor%20Quotations/Some%20File.xlsx, the limit applies to "personal/meganb_contoso_com/Documents/Contracts/Vendor Quotations/Some File.xlsx."

In addition to the above, if files are synced to a PC or Mac, the following limitations apply:

• Each segment of the path (a segment is a file name or folder name like "Promotion" or "Some File.xlsx" in the examples above) can't be more than 255 characters due to operating system limitations.

• The length of the OneDrive root folder (e.g. C:\users\meganb\OneDrive - Contoso) + the relative path of the file (up to 400 chars) cannot be more than 520 characters.

  • The organization name can be updated in the M365 admin center but that will not propagate to existing Sync relationships (only newly established ones). For existing Sync relationships to have the new organization name, users need to unlink and relink their account.

SharePoint Server versions only support up to 260 characters for file and path lengths, Microsoft Excel and older Office version have a lower limit, see KB 326039 for details.

If you exceed any limits, you'll receive an error message.

Thumbnails and previews

Applies to: 

Thumbnails are not generated for images larger than 100 MB.

PDF previews are not generated for files larger than 100 MB.

Number of items that can be synced or copied

Applies to: 

When using onedrive.com, you can only copy up to 2500 files at one time.

Applies to: 

Although SharePoint can store 30 million documents per library, for optimum performance we recommend syncing no more than 300,000 files across all document libraries. Performance issues can occur if you have 300,000 items or more across all libraries that you are syncing, even if you are not syncing all items within those libraries.

Notes: 

• If you are uploading, downloading, or moving a large number of files at once, you may need to wait an extended period of time before the sync process can complete. The desktop app showing "syncing" icon or displaying "processing changes" during this period is not necessarily an indication of a problem. You can always click the OneDrive taskbar icon to see the status of content that is in the process of syncing. To help reduce sync times, we recommend reviewing and possibly modifying your bandwidth settings before starting your upload or download. You can also read how to Choose which OneDrive folders to sync to your computer.

• There are other SharePoint limits on viewing a document library using the web that may affect how you structure your files in OneDrive.

Libraries with Information Rights Management enabled

Applies to: 

Libraries can be synchronized as read/write with sync app for Windows build 17.3.7294.0108 or later, or OneDrive for Mac build 18.151.0729.0014 or higher.

Note: Admins: Learn how to configure the Azure Rights Management service.

Differential sync

Applies to: 

Differential sync is possible for Microsoft Office files in the new file format, .docx, .pptx, .xlsx.

This is part Office integration and requires that you have:

• Office 2016 Click To Run (version 16.0.6741.2027 or higher). You must also have OneDrive (version 17.3.6386.0412 or higher).

• Office 2016 MSI and have the following update installed: October 4, 2016, update for Office 2016 (KB3118262). You must also have OneDrive (version 17.3.6386.0412 or higher).

• The "Use Office applications to sync Office files" setting turned on in the Office tab of OneDrive settings (PC) or OneDrive Preferences (Mac).

For other file types, differential sync is available globally.

Note: OneNote files are not included, see below.

Libraries with specific columns or metadata

Applies to: 

If you have libraries with Checkout, or Validation columns, or when Draft Item Security is set to either Only users who can edit or Only users who can approve items in Version Settings of the library:

• For SharePoint document libraries, these items will be synchronized as read-only.

• For OneDrive libraries, OneDrive will show a lock icon ( ) next to the sync status and the user will not be able to synchronize the library until the mentioned settings have been removed. 

Instructions for removing sync-blocking column settings

Require Check Out 

1. Browse to the document library that you want to configure.

2. In the toolbar, on the Library tab, in the Settings group, choose Library Settings.

3. In General Settings, choose Versioning settings.

4. In Require Check Out, select No (default).

Draft Item Security 

1. Browse to the document library that you want to configure.

2. In the toolbar, on the Library tab, in the Settings group, choose Library Settings.

3. In General Settings, choose Versioning settings.

4. In Draft Item Security select Any user who can read items (default).

Content Approval 

1. Browse to the document library that you want to configure.

2. In the toolbar, on the Library tab, in the Settings group, choose Library Settings.

3. In General Settings, choose Versioning settings.

4. In Content Approval select No (default) for Require content approval for submitted items.

Required Column 

1. Browse to the document library that you want to configure.

2. In the toolbar, on the Library tab, in the Settings group, choose Library Settings.

3. In the Columns section of the page ensure no columns are in the Required section.

Note: When the Management of content types is enabled, the information regarding require columns won't be presented, and in some cases by opening them the required setting, won't be visible as well. Make sure the management of content types is disabled to make this process faster, and re-enable it when done if necessary.

Exclude from Offline Client - Library level

1. Browse to the document library that you want to configure.

2. In the toolbar, on the Library tab, in the Settings group, choose Library Settings.

3. In General Settings, choose Advanced settings.

4. In Offline Client Availability select Yes (default).

Exclude from Offline Client - Site collection level

1. Browse to the site collection that you want to configure.

2. In the toolbar, on the Site tab, in the Settings group, choose Site Settings.

3. Under Search, choose Search and offline availability.

4. In Offline Client Availability select Yes (default).

Limited-access user permission lockdown mode

1. Browse to the Site Settings that you want to configure.

2. In the settings choose Site collection features under the Site Collection Administration heading. ​

3. Find Limited-access user permission lockdown mode and if its enabled, disable it and verify the behavior.

Permissions

1. Browse to the document library that you want to configure.

2. In the toolbar, on the Library tab, in the Settings group, choose Library Settings.

3. Find Permissions for this document library and then Check Permissions for the user

4. To ensure the user has high-enough permissions to have the file sync in more than read only mode, the level must be Contribute or higher.

Validation

1. Browse to the document library that you want to configure.

2. In the toolbar, on the Library tab, in the Settings group, choose Library Settings.

3. Under General Settings, select Validation Settings

4. Remove any column validation and select Save.

Learn more about how to manage Data and lists in SharePoint.

Windows specific restrictions and limitations

Applies to: 

File Explorer displays the first 35 characters of a site library's name and site name combination for a library that you have synchronized. This doesn't affect the ability to sync these items within the limits that are described in this article.

Roaming, Mandatory, and Temporary Windows profiles aren't supported. The OneDrive sync app only supports users who can write to OneDrive application directories.

Additionally, the OneDrive sync app is only supported in Virtual Desktop Infrastructure (VDI) environments in the following cases:

• Virtual desktops that persist between sessions.

• Non-persistent environments that use Windows Virtual Desktop preview.

• Non-persistent environments that have FSLogix Apps 2.8 or later, FSLogix Office 365 Container, and a Microsoft 365 subscription.

Read more about using the sync app on virtual desktops.

For the sync app to work as designed, the following requirements must be met:

• The application must be installed on the local computer.

• The user must be able to write to the user profile.

• Data that's written to the user profile must be saved to the local hard disk and be available without a network connection.

• Folders must not have the SetCaseSensitiveInfo setting enabled.

OneDrive Files On-Demand is supported on Windows 10 2017 Fall Creators Update and later versions, or Windows Server 2019 and later versions, or Mac OS X Mojave (10.14) or newer.

macOS specific restrictions and limitations

Applies to: 

Case-sensitive formatted disk volume isn't supported.

Note: Please note that Invalid characters restrictions also apply to macOS.

Troubleshooting hints and tips

Follow these hints & tips to get the most out of OneDrive and to make sync as trouble-free as possible.

OneDrive system requirements

Applies to: 

OneDrive requires an active Microsoft account, or a work or school account. Your PC must also meet certain operating systems and file system requirements.  Read more about the OneDrive system requirements

Support and Recovery Assistant

Applies to: 

The Support and Recovery Assistant app can help you identify and fix several issues with OneDrive for work or school sync.  Read how to use the Microsoft 365 Support and Recovery Assistant.

If your account or environment is not supported by the Support and Recovery Assistant, read how to Fix OneDrive for Business sync problems.

Only sync what you need

Applies to: 

OneDrive Files On-Demand helps you access all your files in OneDrive without having to download all of them and use storage space on your device. Learn more about OneDrive Files On-Demand.

You can also download fewer files by choosing which OneDrive folders to sync to your computer.

Note: You won't lose files or data by disabling or uninstalling OneDrive on your computer.

Check you're not syncing too many files

Applies to: 

If OneDrive sync seems to be stuck for a long time or the status shows "Processing 0KB of xMB" it could be because you have a lot of files in your OneDrive or a lot of new files to be uploaded. If you have more than 100,000 files, sync can take a long time.

Note: For transferring large files or lots of files, we recommend adding the files to the OneDrive desktop app rather than the using Upload button on the website.

To see how many files you have in your OneDrive:

1. Open File Explorer.

2. Right-click the OneDrive folder and select Properties.
   
   

3. If the Contains number is more than 100,000 you should consider which OneDrive folders to sync to your computer.

If the sync is already in process, you can Pause and Resume your sync to get things going again.

1. Select the white or blue OneDrive cloud icon in the notification area, at the far right of the taskbar.

   

   Note: You might need to click the Show hidden icons arrow next to the notification area to see the OneDrive icon, or click and start typing "select which icons" to display the notification area settings option, and then show Microsoft OneDrive. If the icon still doesn't appear in the notification area, OneDrive might not be running. Click  , type OneDrive in the search box, and then click OneDrive (not "OneDrive for work or school" because that's an older version) in the search results.

2. Select More > Pause syncing... , and select either 2, 8 or 24 hours.

3. Select More again and select Resume syncing

Make sure you don't have duplicate filenames

Applies to: 

You may have sync conflicts if you're uploading multiple files on the OneDrive website at the same time, or if you made changes in your OneDrive folder on another PC that is syncing at the same time.

Sync issues can also occur if you edit files offline.

To reduce sync conflicts, rename the edited files or folders to something new or unique, and then save it again.

Learn more

Applies to: 

More fixes for recent OneDrive issues

Fix sync issues with personal OneDrive

Learn about OneDrive Files On-Demand

Applies to: 

Fix OneDrive for work or school sync problems

Learn about OneDrive Files On-Demand

Fix sync issues with SharePoint

Need more help?

	Get online help See more support pages for OneDrive and OneDrive for work or school. For the OneDrive mobile app, see Troubleshoot OneDrive mobile app problems. OneDrive Admins can also view the OneDrive Tech Community, Help for OneDrive for Admins.
	Contact Support If you still need help, contact support through your browser or shake your mobile device while you're in the OneDrive app. OneDrive Admins can contact Microsoft 365 for business support.
	Got feedback? OneDrive UserVoice is your place to suggest the features you'd like to see us add to OneDrive. While we can't guarantee any specific features or timelines, we will respond to every suggestion that gets at least 500 votes. Go to the OneDrive UserVoice.