How to Fix Microsoft Teams Files Not Opening or Uploading
Applies to
Microsoft Teams for Windows, macOS, web, work, school, and personal accounts
Last updated
6 July 2026
Problem
Files in Microsoft Teams will not open, upload, preview, or download. You may see an error when opening Word, Excel, PowerPoint, PDF, or image files. Uploads may get stuck, fail completely, or show a message that the file cannot be added.
This is usually caused by internet connection problems, file permission issues, unsupported file types, OneDrive or SharePoint sync problems, file size limits, browser cache, or a temporary Teams app fault.
Solution
Check your connection, confirm you have permission to access the file, try opening it in the browser, and verify that OneDrive or SharePoint is working correctly. If uploads fail, check the file name, file size, and storage location before trying again.
Step by step instructions
Check whether the issue affects one file or all files
Start by identifying the scope of the problem.
Test a few different files in Teams.
Check whether the issue affects:
- One specific file
- One channel or chat
- All files in Teams
- Only uploads
- Only previews
- Only the desktop app
If only one file fails, the problem may be file specific. If all files fail, the issue is more likely to be Teams, browser, OneDrive, SharePoint, or your connection.
Open Teams on the web
If files do not open in the desktop app, try Teams in a browser.
Go to:
Sign in with the same account.
Open the same chat, channel, or team.
Try opening the file again.
If the file opens in the browser, the desktop app may need to be restarted, repaired, updated, or reinstalled.
Open the file in SharePoint or OneDrive
Files shared in Teams channels are usually stored in SharePoint. Files shared in Teams chats are usually stored in OneDrive.
In Teams, open the file menu.
Choose Open in browser, Open in SharePoint, or Open in OneDrive if available.
If the file opens there, Teams may be having a preview or app issue.
If the file does not open in SharePoint or OneDrive, the issue may be permissions, storage, or the file itself.
Check file permissions
You may not have permission to open or edit the file.
Ask the owner to confirm that you have access.
Common permission problems include:
- The file was shared with the wrong person
- You were removed from the team or chat
- The file was moved or deleted
- Guest access is restricted
- The file owner’s OneDrive account is unavailable
- The SharePoint site has limited permissions
If you are using a work or school account, your IT team may need to check SharePoint or OneDrive permissions.
Check the file name
Teams, OneDrive, and SharePoint may reject files with unsupported names or characters.
Before uploading, rename the file with a simple name.
Avoid using unusual characters such as:
- Quotation marks
- Asterisks
- Colons
- Question marks
- Angle brackets
- Vertical bars
Use a clear file name with letters, numbers, spaces, hyphens, or underscores.
Check file size and type
Large files may take longer to upload or fail on unstable connections.
Check the file size before uploading.
If the file is very large:
- Compress it if possible
- Upload it directly to OneDrive or SharePoint
- Use a stronger internet connection
- Avoid uploading while on mobile data
- Try from a desktop browser instead of the Teams app
Also confirm that the file type is supported by Teams preview. Some files may upload successfully but not preview inside Teams.
Try uploading from OneDrive or SharePoint instead
If direct upload through Teams fails, upload the file through OneDrive or SharePoint.
For OneDrive, go to:
For Microsoft 365 work or school accounts, you can also open OneDrive from:
After uploading, share the file link in Teams.
For channel files, open the channel’s Files tab and choose Open in SharePoint if available, then upload directly there.
Clear Teams cache or restart the app
If files are stuck loading in the desktop app, Teams cache may be causing the issue.
Fully quit Teams.
Restart your computer.
Open Teams again and try the file.
If the issue continues, repair or reset Teams from Windows app settings if available.
Check browser cache and extensions
If files do not open in Teams web, your browser may be blocking previews or downloads.
Try these checks:
- Refresh the browser page
- Clear browser cache and cookies
- Disable ad blockers or privacy extensions temporarily
- Try private browsing mode
- Try another browser
Then return to https://teams.microsoft.com and test the file again.
Check Microsoft 365 service health
If many users cannot open or upload files, the issue may be with Teams, OneDrive, or SharePoint services.
For work or school accounts, ask your IT administrator to check Microsoft 365 service health in the admin centre.
This is especially important if the problem affects multiple teams, channels, or users at the same time.
Optional methods or tools
- Use https://teams.microsoft.com to test whether the desktop app is the issue
- Open channel files directly in SharePoint when Teams preview fails
- Upload large files to OneDrive first and share a link in Teams
- Try another browser if Teams web cannot preview files
- Ask your IT team to check SharePoint and OneDrive permissions
Best practices or tips
- Use simple file names without unusual characters
- Keep files organised in the correct Teams channel
- Avoid uploading very large files over weak WiFi
- Share links instead of reuploading duplicate copies
- Confirm permissions before sharing files with guests or external users
Microsoft Teams file problems are often linked to OneDrive and SharePoint because Teams uses those services to store and manage shared files. If a file will not open in Teams, testing it directly in OneDrive or SharePoint is one of the quickest ways to identify whether the problem is with Teams preview or the file storage location.
When uploads fail, the cause is usually file size, file name, connection quality, or permissions. Using simple file names, checking access, and uploading large files directly through OneDrive or SharePoint can make file sharing in Teams more reliable.
