Invalid file names and file types in OneDrive, OneDrive for Business, and SharePoint

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 ( OneDrive icon ), OneDrive for Business ( OneDrive for Business icon ) or SharePoint Online.

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

What's New

14 December 2018: Updated information in File upload size and Windows specific limitations.

7 December 2018: Added more information on Outlook .pst data files to blocked file types.

24 September 2018: Removed icon_t and _w from the Invalid file names list.

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 be synced

Syncing too many files

Elevated privileges

Information Rights Management

Duplicate filenames

Shared with Me

Differential sync

Guest accounts

Libraries with specific columns

Authenticated proxies

Windows specific limitations

OneNote notebooks 

macOS specific limitations

Restrictions

Invalid characters

Applies to:  OneDrive icon OneDrive for Business icon

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, OneDrive for Business on Office 365, and SharePoint Online

Characters that aren't allowed in file and folder names in OneDrive for Business on SharePoint Server 2013

" * : < > ? / \ |

~ " # % & * : < > ? / \ { | }.

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 Office 365, see Enabling # and % Support on the SharePoint blog to learn how to allow these characters.

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

Invalid file or folder names

Applies to:  OneDrive icon OneDrive for Business icon

These names aren't allowed for files or folders: .lock, CON, PRN, AUX, NUL, COM1 - COM9, LPT1 - 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 Online that begins with a tilde (~).

Invalid or blocked file types

Applies to:  OneDrive icon   OneDrive for Business icon

There are no blocked file types in OneDrive, but if you are a OneDrive for Business 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.

Notes: 

  • Whereas .PST files aren’t actively blocked by OneDrive, .PST files will be synced every time you close Outlook, even if no change was made to the .PST file. This can result in high network traffic, which may result in .PST file throttling.

  • To avoid excessive or lengthy re-syncing, .PST files that are in active use shouldn't be syncing to OneDrive. 

  • If you want to move your Outlook .PST Data File, read How to remove an Outlook .pst data file from OneDrive.

Network or mapped drives

Applies to:  OneDrive icon OneDrive for Business icon

You can't add a network or mapped drive as your OneDrive sync location.

OneDrive doesn't support symbolic links where the Link and Target are both located in the same library location.

Note: Having two different paths to the same set of files in the target folder may lead to performance and stability issues. Symbolic links provide an alternate path to an existing folder and are typically created using the mklink command.

Elevated privileges

Applies to:  OneDrive icon OneDrive for Business icon

OneDrive can’t be run with elevated privileges.

Shared with Me

Applies to:  OneDrive for Business icon

You can't synchronize the Shared with Me view grouping of files from a OneDrive for Business site.

Guest accounts

Applies to:  OneDrive icon OneDrive for Business icon

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

Authenticated proxies

Applies to:  OneDrive icon OneDrive for Business icon

Authenticated proxies aren’t supported in OneDrive.

OneNote notebooks 

Applies to:  OneDrive for Business icon

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.

Read how to Move a OneNote notebook to OneDrive.

Limitations

File upload size

OneDrive
OneDrive icon

OneDrive for Business
OneDrive fro Business

50GB

15GB

Note: For more help, read to how Fix problems uploading files on the OneDrive website.

File name and path lengths

Applies to:  OneDrive icon OneDrive for Business icon

The entire path, including the file name, must contain fewer than 400 characters for OneDrive, OneDrive for Business and SharePoint Online. If you exceed that limit, you'll receive an error message.

Notes: 

  • SharePoint Server versions only support up to 260 characters for file and path lengths.

  • Some older Office version may have a lower limit, see KB 326039 for details.

Thumbnails and previews

Applies to:  OneDrive icon OneDrive for Business icon

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

Applies to:  OneDrive for Business icon

Although SharePoint Online 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 Online 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:  OneDrive for Business icon

Libraries can be synchronized as read/write with OneDrive desktop app for Windows build 17.3.7294.0108 or later, or OneDrive for Mac build 18.111.0603.0002 or higher.

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

Differential sync

Applies to:  OneDrive for Business icon

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

This is part Office Integration and requires:

  • 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).

  • You must have Office Integration turned on in the Office tab of OneDrive settings (PC) or OneDrive Preferences (Mac).

Note: OneNote files are not included, see below.

Libraries with specific columns or metadata

Applies to:  OneDrive for Business icon

If you have libraries with Checkout, Required columns or metadata, 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 ( OneDrive file locked icon ) next to the sync status and the user will not be able to synchronize the library until the mentioned settings have been removed. 

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.

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

Windows specific restrictions and limitations

Applies to:  OneDrive for Business icon

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 desktop app only supports users who can write to OneDrive application directories.

Additionally, the OneDrive desktop app doesn't support client sessions that are hosted on Windows 2008 Terminal Services, Windows Server 2012, or Windows Server 2016 Remote Desktop Services (RDS). This only applies to non-persistent Virtual Desktop Infrastructure (VDI), except with Windows Virtual Desktop (WVD). OneDrive is supported if used with WVD. Persistent VDI is also supported by the OneDrive desktop app.

For the OneDrive desktop 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.

OneDrive Files On-Demand is only supported on Windows 10 Fall Creators Update and later versions.

macOS specific restrictions and limitations

Applies to:  OneDrive icon OneDrive for Business icon

Case-sensitive formatted disk volume isn't supported.

Office integration (co-authoring and in-app sharing) isn't currently supported.

OneDrive Files On-Demand 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 icon OneDrive for Business icon

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:  OneDrive for Business icon

The Support and Recovery Assistant app can help you identify and fix several issues with OneDrive for Business sync. Read how to use the Office 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 icon OneDrive for Business icon

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:  OneDrive icon OneDrive for Business icon

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.

    OneDrive 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.

    OneDrive SyncClient with blue cloud and white cloud icons

    Note: You might need to click the Show hidden icons arrow next to the notification area to see the OneDrive icon, or click Press the Windows key 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  Press the Windows key , type OneDrive in the search box, and then click OneDrive (not "OneDrive for Business" as that may be an older version) in the search results.

  2. In the activity center, select MorePause syncing... , and select either 2, 8 or 24 hours.

  3. In the activity center, select More again and select Resume syncing

Make sure you don't have duplicate filenames

Applies to:  OneDrive icon OneDrive for Business icon

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:  OneDrive icon

More fixes for recent OneDrive issues

Fix sync issues with personal OneDrive

Learn about OneDrive Files On-Demand

Applies to:  OneDrive for Business icon

Fix OneDrive for Business sync problems

Learn about OneDrive Files On-Demand

Fix sync issues with SharePoint Online

Need more help?

Online

Get online help
See more support pages for OneDrive and OneDrive for Business.
For the OneDrive mobile app, see Troubleshoot OneDrive mobile app problems.

Email Support icon

Email support
If you still need help, shake your mobile device while you're in the OneDrive app or email the OneDrive support team. To contact One Drive for Business support from your PC or Mac, open the activity center, select More > Send feedback > I don't like something.

One Drive for Business Admins can also view the OneDrive for Business Tech Community, Help for OneDrive for Business Admins, or contact Office 365 for business support.

Office 365 community forums

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.

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