Microsoft 365 Error Codes

How to Fix Microsoft 365 Sign-In Error 1001 with Administrator Accounts

John Wilson Oct 9, 2026 868 views

Question details

The user is unable to sign into Microsoft 365 due to Error 1001, which is often triggered by conflicting Office identities, cached credentials, or complexities involving separate Windows administrator and standard accounts.

Fixing Microsoft 365 Sign-In Error 1001 with Administrator Accounts

Product: Microsoft 365
Device & OS: Windows
Scenario: Attempting to authenticate and sign into Microsoft 365 via a web browser or local desktop applications.
Observed behavior: The sign-in process fails, displaying Error 1001 and preventing access to Office services or applications.

Before you start

Before proceeding with folder deletions or registry modifications, ensure all Office applications are completely closed and consider creating a Windows System Restore point to prevent accidental data loss.

Solution 1Recommended

Clear Local Office Identity Cache and OneAuth Folders

This method forces local Microsoft Office applications to rebuild corrupted or conflicting identity profiles, which is the most common fix for Error 1001 on desktop apps.

When standard and administrator accounts conflict, the local authentication cache can become corrupted. Deleting the specific identity cache folders forces Office to prompt for a clean sign-in.

Close all Microsoft applications

Ensure that all Office applications, including Microsoft Teams and OneDrive, are completely closed. You may need to use Task Manager to verify they are not running in the background.

Navigate to the AppData folder

Press the Windows Key + R to open the Run dialog. Type %localappdata%\Microsoft and press Enter.

Locate and remove identity folders

Find the folders named 'OneAuth' and 'IdentityCache'. Move these folders to your desktop as a backup, or delete them if you are comfortable doing so.

Restart and sign in

Restart your computer. Launch a Microsoft Office application and attempt to sign in again with your standard or administrator credentials.

Clear Local Office Identity Cache and OneAuth Folders

Administrator Privileges: You will need administrator permissions to access and modify certain folders within the local AppData directory.

Solution 2

Isolate Browser Sign-In Issues with InPrivate Mode

Use this solution if Error 1001 is occurring specifically when trying to access Microsoft 365 through a web browser.

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Frequently Asked Questions

What exactly causes Microsoft 365 Error 1001?

Error 1001 is typically caused by conflicting Office identity profiles, corrupted cached credentials, or discrepancies that occur when alternating between Windows administrator and standard accounts during Office sign-ins.

Do I need to edit the Windows Registry to fix Error 1001?

While advanced Microsoft guidance may suggest removing conflicting identity keys in the registry, this should only be done if you fully understand the consequences and have administrator support. Rebuilding the OneAuth and IdentityCache folders is usually safer and resolves the issue in most cases.

Why does Error 1001 happen more often with Administrator accounts?

Having separate standard and administrator Windows accounts can confuse the Microsoft authentication broker, especially if Office applications are launched with different privilege levels, causing local credentials to overlap and conflict.

Will I lose my files if I delete the OneAuth and IdentityCache folders?

No. These folders only store temporary login session data and cached credentials. Deleting them simply forces Microsoft Office to prompt you to sign in again to recreate a fresh, uncorrupted identity profile. Your documents and files remain completely safe.

Microsoft Office Error Codes