Microsoft 365 Error Codes

How to Fix Microsoft 365 Error 1001 When Opening SharePoint Files

Olivia Miller Oct 22, 2026 869 views

Question details

The user is unable to sign in to Microsoft 365 or open SharePoint documents using desktop applications due to a 'Something Went Wrong [1001]' error.

How to Fix Microsoft 365 Error Something Went Wrong [1001] for SharePoint Files

Product: Microsoft 365
Device & OS: Windows
Scenario: Attempting to access SharePoint files or authenticate an account within Microsoft Office desktop applications.
Observed behavior: The application displays Error 1001 and blocks access, which is typically caused by corrupted authentication tokens or cached identity data.

Before you start

Ensure you have completely closed all Microsoft 365 applications, including Microsoft Teams and Outlook, as running background processes will prevent you from modifying the required system folders.

Solution 1Recommended

Clear OneAuth and IdentityCache Folders

Removing corrupted authentication tokens forces Microsoft 365 to generate fresh login data, resolving the 1001 sign-in error.

Microsoft 365 stores login sessions locally to speed up authentication. When these cached files become corrupted, they cause a continuous authentication loop resulting in Error 1001. Moving these files forces the system to rebuild them upon your next login.

Close All Microsoft Applications

Ensure that all Office desktop applications (Word, Excel, Outlook) and Microsoft Teams are fully closed. Check your system tray to ensure no background processes are running.

Navigate to the AppData Folder

Press the Windows Key + R on your keyboard to open the Run dialog box. Type '%localappdata%\Microsoft' and press Enter to open the directory in File Explorer.

Move the Cache Folders

Locate the folders named 'OneAuth' and 'IdentityCache'. Select both folders, right-click, and choose 'Cut'. Paste them onto your computer desktop to keep them as a safe backup.

Relaunch and Sign In

Open Outlook or another Office application. You will be prompted to sign in again. Enter your credentials to generate new, uncorrupted authentication tokens.

What to do if the error persists: If the issue is not resolved, close your Office applications and copy the backup OneAuth and IdentityCache folders from your desktop back into the Microsoft AppData folder. If asked to overwrite existing folders, select 'No'.

Solution 2

Access SharePoint Files via Microsoft 365 Web

If you are unable to perform system folder modifications, using the web versions of Microsoft 365 is an immediate workaround.

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Frequently Asked Questions

What causes the Microsoft 365 Error 1001?

Error 1001 is typically caused by corrupted authentication tokens, network interruptions during a login phase, or outdated cached identity data stored locally in the Microsoft AppData folders on your Windows device.

Will I lose my SharePoint files if I delete the IdentityCache folder?

No. Moving or deleting the IdentityCache and OneAuth folders only resets your local login session data. Your actual documents are stored securely in the cloud on SharePoint and will remain unaffected.

Why does Error 1001 persist after uninstalling and reinstalling Microsoft 365?

Standard uninstallation processes often leave behind hidden user configuration folders, including AppData cache. Because the corrupted IdentityCache and OneAuth folders are retained, the error returns immediately upon reinstalling the software.

What should I do if clearing the cache does not fix the sign-in error?

If clearing the folders fails, you should restore your backup folders to their original location without overwriting new files. The issue may lie with an expired server-side token, requiring assistance from your IT administrator or Microsoft Support.

Microsoft Office Error Codes