OneDrive Error Codes

How to Fix Upload Blocked Error When Saving Microsoft 365 Files

Emma Brown Oct 9, 2026 869 views

Question details

The user is unable to save files to OneDrive via Microsoft 365 applications, encountering a specific error message stating the upload is blocked.

How to Fix Upload Blocked Errors When Saving Microsoft 365 Files

Product: Microsoft 365 and OneDrive
Device & OS: Windows
Scenario: Saving an edited document or a new file to a OneDrive synchronized folder using Microsoft Office applications.
Observed behavior: The application displays the message 'Upload Blocked: We ran into a problem saving this file', and the file fails to sync to the cloud.

Before you start

Ensure you are connected to a stable internet connection and verify that your OneDrive icon in the system tray does not display any immediate sync conflict warnings.

Solution 1Recommended

Clear Office and OneDrive Cached Credentials

Removing outdated or corrupted Microsoft credentials from Windows forces the applications to re-authenticate, which often resolves upload blocks.

Cached credentials for Microsoft Office and OneDrive can occasionally become corrupted or fall out of sync with Microsoft's servers. Clearing them from the Windows Credential Manager allows you to establish a fresh, error-free connection.

Sign out and close applications

Sign out of your Microsoft Office applications and OneDrive. Once signed out, completely close all running Office apps, including Word, Excel, and PowerPoint.

Open Windows Credential Manager

Click the Windows Start button, type 'Control Panel', and press Enter. Navigate to 'User Accounts' and select 'Credential Manager', then click on 'Windows Credentials'.

Remove cached credentials

Scroll through the list and locate any entries related to 'OneDrive Cached Credentials' as well as 'MicrosoftOffice15' or 'MicrosoftOffice16'. Click on each entry and select 'Remove'.

Restart and sign back in

Restart your computer. Open a Microsoft 365 application, sign back into your Microsoft account, and attempt to save your file again.

Clear Office and OneDrive Cached Credentials

No Data Loss: Clearing credentials only removes saved login tokens. Your actual files and documents will not be deleted.

Solution 2

Reduce File Count in the Destination Folder

OneDrive can experience sync issues if a single folder contains an excessive number of files.

Free Microsoft Office alternative

Try WPS Office for Seamless and Error-Free Cloud Saving

If you are tired of troubleshooting OneDrive upload blocks and Microsoft 365 sync errors, consider switching to WPS Office. It is a lightweight, free alternative that offers reliable file saving without complex credential caching issues.

1. Download and Install: Visit the official WPS Office website to download the free suite. Run the installer to quickly set it up on your device.
2. Open Your Files: Launch WPS Office and directly open your existing Microsoft Word, Excel, or PowerPoint files without losing any formatting.
3. Save Without Errors: Edit your documents and save them locally or to WPS Cloud instantly, avoiding the 'Upload Blocked' errors entirely.

Fully compatible with Microsoft Office formats including .docx, .xlsx, and .pptx.Built-in, stable WPS Cloud storage that prevents upload blocks and sync conflicts.Lightweight software architecture that does not rely on complex Windows Credential Manager tokens.Completely free to use with a highly familiar user interface for an easy transition.

microsoft office alternative - wps office

Frequently Asked Questions

Why does Microsoft 365 say my upload is blocked?

This error typically occurs when there is a synchronization conflict with OneDrive, often caused by outdated login tokens in the Windows Credential Manager, or if the destination folder has exceeded its optimal file capacity.

Can having too many files in a folder cause OneDrive upload errors?

Yes, if a single folder within OneDrive contains more than 5,000 files, it can struggle to index and sync new changes, resulting in the 'Upload Blocked' error when attempting to save.

Will clearing my Windows Credentials delete my saved documents?

No, clearing Windows Credentials only removes saved passwords and authentication tokens. It does not affect your personal files, documents, or data stored on your hard drive or in your cloud storage.

Microsoft Office Error Codes