This article describes the restrictions and limitations that apply to files, file names, and file types when you sync with OneDrive for home, OneDrive for work or school, or SharePoint in Microsoft 365.
Use the links in In this article to find the restriction or limit that matches your issue. Each section identifies the OneDrive account types it applies to. For SharePoint document libraries, also check the library-specific settings and limitations.
Note
For restrictions and limitations that apply to the earlier version of OneDrive for Business (groove.exe), SharePoint 2013, and SharePoint 2016, see KB 2933738.
What's new
April 22, 2026: Started rollout of the public preview for syncing up to 1,000,000 items. Review the preview requirements and exclusions before using this limit.
January 28, 2025: OneDrive for Mac now supports invalid characters.
In this article
Restrictions
Invalid characters
Applies to: OneDrive for home and OneDrive for work or school.
Certain characters have special meanings when you use them in file names in OneDrive, SharePoint, Windows, and macOS. For example, "*" represents a wildcard, and "\" appears in file name paths. If a file or folder you want to upload to OneDrive contains any of the characters in the following list, it might prevent files and folders from syncing. Rename the file or folder to remove these characters before you upload it.
The following characters aren't allowed in file and folder names in OneDrive for home or OneDrive for work or school:
" * : < > ? / \ |
Note
- You can't use leading and trailing spaces in file or folder names.
- 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 Return.
- 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 save an Office file through the Backstage view to a OneDrive or SharePoint folder, you can't save the file if the folder name contains ; (semicolon).
- If you use Office 2010, you can't use "&" in file and folder names.
- For automatic renaming behavior, including changes from a comma to ^J, see Why has my filename changed?.
Invalid file or folder names
Applies to: OneDrive for home and OneDrive for work or school.
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 ~$.
Note
- You can't use _vti_ anywhere in a file name.
- You can't use forms when the folder or file is at the root level of a library.
- A folder name can't start with either ゛ or ဧ.
Invalid or blocked file types
Applies to: OneDrive for home and OneDrive for work or school.
Temporary TMP files don't sync to OneDrive. For more information, see OneDrive status stuck on "Sync pending".
Files that your local computer uses, such as desktop.ini on Windows or .ds_store on macOS, don't normally sync. If these files get uploaded to OneDrive during a migration, the sync app deletes the cloud copy and leaves the local copy.
Outlook .PST files are supported, but the sync app syncs them less frequently than other file types to reduce network traffic. To move .PST files out of OneDrive, see How to remove an Outlook PST data file from OneDrive.
For work or school accounts, admins can block syncing of specific file types. If Known Folder Move is enabled and configured through Group Policy, .PST files migrate. Outlook might show errors after migration because it's still looking for the .PST files at their original location.
For OneDrive for work or school, your admin might prevent the sync app from uploading specific file types. Contact your admin if an organizational policy blocks a file you need to sync.
SharePoint in Microsoft 365 doesn't have a general list of blocked file types. Some custom-script file types can be uploaded but won't work unless the site allows custom script. For details and the separate restrictions for earlier SharePoint Server versions, see Types of files that cannot be added to a list or library.
Network or mapped drives
Applies to: OneDrive for home and OneDrive for work or school.
You can't add a network or mapped drive as your OneDrive sync location. OneDrive doesn't support syncing by using symbolic links or junction points.
Elevated privileges
Applies to: OneDrive for home and OneDrive for work or school.
OneDrive doesn't support running with elevated privileges. When you run with elevated privileges, OneDrive menu items aren't available in File Explorer. For troubleshooting, see Unable to share OneDrive files.
For multi-user computers or environments where executable files shouldn't run from user profiles, admins can review per-machine sync app installation. A per-machine installation doesn't change the restriction on running OneDrive with elevated privileges.
Sharing
Applies to: OneDrive for home and OneDrive for work or school.
You can't share this item because the folder contains too many items
When you share a folder, you can include up to 50,000 sub-items within that folder and its subfolders.
To overcome this restriction, move some items into another folder that's outside the original folder, or choose individual files to share.
You can't break inheritance for this item because the list or library contains too many items with unique permissions
The supported limit for unique permissions in a list or library is 50,000 items. However, the recommended general limit is 5,000 items. Changing more than 5,000 uniquely permitted items at one time takes longer. For large lists, design the list to have as few unique permissions as possible.
Shared with me
You can't synchronize the Shared with me view grouping of files from a OneDrive for work or school site.
Delivery failed to these recipients or groups error when sharing
You might receive this error message when you try to share to an address that isn't associated with a Microsoft account.
How many OneDrive accounts?
Applies to: OneDrive for home and OneDrive for work or school.
Number of OneDrive accounts
You can sign in to and sync a limited number of accounts at the same time. Each device can have up to one OneDrive for home account and nine OneDrive for work or school accounts. For macOS devices, only one business account from the same organization can sync at a time.
OneDrive guest accounts
OneDrive supports syncing content as an external or guest user. For requirements, see B2B sync.
Authenticated proxies
Applies to: OneDrive for home and OneDrive for work or school.
OneDrive doesn't support authenticated proxies.
If you see the error message "Your proxy settings require authentication" or the error code 0x8004de42 when you try to sign in to OneDrive, check that you're not using an authenticated proxy to connect to OneDrive.
OneNote notebooks
Applies to: OneDrive for work or school.
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 isn't currently supported.
Once a OneNote notebook is saved in OneDrive, if you are syncing the folder that contains the notebook, you find a stub .url file, which opens the notebook on the website.
OneNote notebooks saved in OneDrive or SharePoint are limited to 2 GB.
Read how to Move a OneNote notebook to OneDrive.
Virus detection
Applies to: OneDrive for work or school.
Microsoft 365 scans files uploaded to OneDrive and SharePoint and flags files when it detects malware. A file might sync to your computer before it's marked as malware. After the file is marked, you can't open the synced file locally.
You can check the status of files through the OneDrive web app. Infected files are marked with a red symbol beside the file name, indicating that the file is flagged as malware.
Important
Built-in virus detection isn't a replacement for anti-malware protection on your devices. For details, see Built-in virus protection in SharePoint, OneDrive, and Microsoft Teams.
Limitations
File upload and download sizes
Applies to: OneDrive for home and OneDrive for work or school.
| Maximum | Upload | Download |
|---|---|---|
| Sync | 250 GB | 250 GB |
| Individual files | 250 GB | 250 GB |
| Files within a zip | 250 GB | 250 GB |
Note
These limits apply to files, not your total storage. For any file larger than a few GB, use the OneDrive sync app instead of the website upload feature.
File name and path lengths
Applies to: OneDrive for home and OneDrive for work or school.
Different apps and Office versions have different limits. The combination of limitations might be unique to your setup.
For platform-specific limits and troubleshooting steps, see What are the file path length limits?.
Thumbnails and previews
Applies to: OneDrive for home and OneDrive for work or school.
The service doesn't generate thumbnails for images larger than 100 MB.
The service doesn't generate PDF previews for files larger than 100 MB.
Note
The service supports thumbnails only for OneDrive-supported file types, such as Office files, PDFs, and selected image and app types.
Number of items that can be synced or copied
Applies to: OneDrive for home and OneDrive for work or school.
Copy files on the OneDrive website
You can copy up to 2,500 files at one time on the OneDrive website.
Standard sync recommendation
For optimum performance outside the public preview described below, we recommend syncing no more than a total of 300,000 items across your cloud storage. Performance issues can occur if you have more than 300,000 items, even if you aren't syncing all items.
Uploading, downloading, or moving many files at once can take a long time. During this time, the OneDrive desktop app status icon shows Syncing or Processing changes.
Public preview: sync up to 1,000,000 items
Support for syncing up to 1,000,000 items per sync instance per device is available in public preview for Windows and macOS. This preview doesn't support virtual desktop infrastructure (VDI) environments.
To participate in this preview, you must meet the following requirements:
- Sync app: Use the latest OneDrive sync app with the OneDrive Insider program enabled. See How to access OneDrive settings.
- Windows 11, Windows Server 2025, or macOS Golden Gate 27.
- Memory: 8 GB RAM minimum (16 GB recommended).
- Storage: Solid-state drive (SSD) required.
- Processor: Intel i5 / AMD Ryzen 5 or later, Snapdragon X Plus or Apple silicon.
- Recommended sync app configuration for Windows or macOS.
Note
- Devices that don't meet these requirements continue to sync at the existing 300,000-item supported limit with no disruption.
- Performance isn't yet optimized for syncing a high volume of read-only files or for accounts under legal hold. Microsoft is actively working to improve performance and reliability for these scenarios.
- Other SharePoint limits on viewing a document library on the web might affect how you structure your files in OneDrive.
Libraries with Information Rights Management enabled
Applies to: OneDrive for work or school.
To sync libraries as read/write, use the OneDrive sync app for Windows build 17.3.7294.0108 or later, or OneDrive for Mac build 18.151.0729.0014 or later.
Note
Admins: Learn how to configure the Azure Rights Management service.
Differential sync
Applies to: OneDrive for work or school.
Differential sync works for Microsoft Office files in the new file format, .docx, .pptx, and .xlsx.
This feature is part of 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 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 aren't included. See OneNote notebooks.
Libraries with specific columns or metadata
Applies to: OneDrive for work or school.
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, you synchronize these items as read-only.
- For OneDrive libraries, OneDrive shows a lock icon (
) next to the sync status and you can't synchronize the library until you remove the settings.
Before you change library or site settings
These procedures are for people who have permission to manage the affected library or site. If you can't access the settings, contact the library owner or your SharePoint admin.
Important
Changes to checkout, draft visibility, content approval, required columns, validation, or permissions affect everyone who uses the library or site. Confirm the changes with the owner before proceeding. Don't remove controls that your organization requires just to enable syncing.
Open library settings
Use these steps whenever a procedure below directs you to open library settings:
- Open the document library that you want to configure.
- Select Settings > Library settings. In the classic experience, on the Library tab, in the Settings group, select Library Settings.
- If a settings panel opens, select More library settings to open the full settings page.
For versioning-related options, see Enable and configure versioning for a list or library.
Require Check Out
- Open library settings.
- Under General Settings, select Versioning settings.
- Under Require Check Out, select No (default).
- Select OK.
Draft Item Security
- Open library settings.
- Under General Settings, select Versioning settings.
- Under Draft Item Security, select Any user who can read items (default).
- Select OK.
Content Approval
- Open library settings.
- Under General Settings, select Versioning settings.
- Under Content Approval, select No (default) for Require content approval for submitted items.
- Select OK.
Required columns
- Open library settings.
- In the Columns section, review which columns are required. With the library owner's approval, change the requirements so that no columns are required.
Note
When you enable Management of content types, information about required columns might not be available. If you need to temporarily disable content type management to access the required-column settings, obtain the library owner's approval first and re-enable it when you're done.
Offline Client Availability at the library level
- Open library settings.
- Under General Settings, select Advanced settings.
- Under Offline Client Availability, select Yes (default).
Offline Client Availability at the site level
- Open the site that you want to configure.
- In the classic toolbar, on the Site tab, in the Settings group, select Site Settings.
- Under Search, select Search and offline availability.
- Under Offline Client Availability, select Yes (default).
Limited-access user permission lockdown mode
- Open Site Settings for the site that you want to configure.
- Under Site Collection Administration, select Site collection features.
- Find Limited-access user permission lockdown mode. If it's enabled and the site owner approves the change, disable it and check whether syncing works.
Permissions
- Open library settings.
- Select Permissions for this document library, and then select Check Permissions for the user.
- To sync the file in more than read-only mode, the user must have Contribute permissions or higher.
Validation
- Open library settings.
- Under General Settings, select Validation Settings.
- Remove the validation that the library owner has approved for removal, and then select Save.
After an approved change, check whether the affected files sync and whether the library or site still behaves as intended.
Learn more about how to manage Data and lists in SharePoint.
Windows-specific restrictions and limitations
Applies to: OneDrive for work or school.
File Explorer displays the first 35 characters of a site library's name and site name combination for a library that you synchronize. This limitation doesn't affect your ability to sync these items within the limits described in this article.
The sync app doesn't support roaming, mandatory, and temporary Windows profiles. The OneDrive sync app supports only users who can write to OneDrive application directories.
The OneDrive sync app supports the following virtual desktop infrastructure (VDI) configurations on supported operating systems:
- Virtual desktops that persist between sessions.
- Non-persistent virtual desktops that use Azure Virtual Desktop.
- Non-persistent virtual desktops that use FSLogix Apps or FSLogix Office Container and a Microsoft 365 subscription.
All non-persistent VDI environments require the latest version of FSLogix and a per-machine installation of the OneDrive sync app. Review the supported operating systems and configuration requirements in Use the sync app on virtual desktops. The 1,000,000-item public preview doesn't support VDI environments.
For the sync app to work as designed, your environment must meet the following requirements:
- The application is installed on the local computer.
- The user can write to the user profile.
- Data written to the user profile is saved to the local hard disk and is available without a network connection.
- Folders don't have the SetCaseSensitiveInfo setting enabled.
For current operating system requirements, see OneDrive system requirements. For Files On-Demand setup, see the guidance for Windows or macOS.
macOS-specific restrictions and limitations
Applies to: OneDrive for home and OneDrive for work or school.
The sync app doesn't support case-sensitive formatted disk volumes.
Note
The Invalid characters restrictions also apply to macOS.
Troubleshooting hints and tips
Follow these hints and tips to get the most out of OneDrive and to make sync as trouble-free as possible.
OneDrive system requirements
Applies to: OneDrive for home and OneDrive for work or school.
OneDrive requires an active Microsoft account or a work or school account. Your device must also meet operating system and file system requirements. See OneDrive system requirements.
Support and Recovery Assistant
Applies to: OneDrive for work or school.
Microsoft Support and Recovery Assistant has been replaced by troubleshooters integrated into Get Help. For the available troubleshooters, see Running troubleshooters in Get Help.
For OneDrive-specific troubleshooting, see Fix OneDrive for work or school sync problems.
Only sync what you need
Applies to: OneDrive for home and OneDrive for work or school.
OneDrive Files On-Demand helps you access your files without downloading all of them and using storage space on your device. See the guidance for Windows or macOS.
You can also download fewer files by choosing which OneDrive folders to sync to your computer.
Note
You don't lose files or data by disabling or uninstalling OneDrive on your computer.
Check you're not syncing too many files
Applies to: OneDrive for home and OneDrive for work or school.
If OneDrive sync seems stuck for a long time or the status shows "Processing 0KB of xMB", you might have many files in OneDrive or many new files to upload. Review the standard sync recommendation and public preview requirements before deciding whether to reduce the number of items.
Note
For transferring large files or lots of files, add the files to the OneDrive desktop app rather than using the Upload button on the website.
To check the file and folder count for your local OneDrive folder on Windows:
Open File Explorer.
Right-click the OneDrive folder and select Properties.
Review the Contains field for the number of files and folders.
This count describes the selected local folder, not all items across your cloud storage. If you aren't participating in the public preview and exceed the 300,000-item recommendation, review how to cancel or stop sync in OneDrive and choose which OneDrive folders to sync.
If syncing is already in progress, try pausing and resuming OneDrive sync.
Make sure you don't have duplicate filenames
Applies to: OneDrive for home and OneDrive for work or school.
You might have sync conflicts if you upload multiple files on the OneDrive website at the same time, or if you make changes in your OneDrive folder on another PC that syncs 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 them again.
Learn more
- More fixes for recent OneDrive issues
- Fix sync issues with personal OneDrive
- Fix OneDrive for work or school sync problems
- Fix sync issues with SharePoint
Need more help?
Account support. For help with your Microsoft account and subscriptions, visit Account & Billing Help.
Technical support. For technical support, select Contact Microsoft Support below, enter your problem and select Get Help.
Mobile users can contact Support by opening the OneDrive app and gently shaking your device.
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