Microsoft 365 Outlook 1001 Error “Something went wrong”

Published by Nyau Wai Hoe - Updated on

Many people use Microsoft Office 365 every day for work because it has a lot of helpful tools. But sometimes, problems happen. A common trouble is the “Something went wrong [1001]” error in Outlook. It pops up suddenly and can really mess up your work. This guide will help you fix the Microsoft Office 365 Outlook 1001 error.

Linked issue: Microsoft Edge “Something went wrong, but we resolved it”

Microsoft 365 Outlook 1001 Error Something went wrong

A brief overview of the Microsoft Outlook 1001 Error

The “Something went wrong [1001]” error in Microsoft 365’s Outlook pops up without warning. It’s annoying because it comes and goes without a clear reason. The main reasons are usually linked to account login problems or messed-up cache files.

Even though Microsoft has tried to fix it with updates, it still happens to some people. Knowing why it happens can help you find a fix, so it doesn’t keep coming back.

  1. Account login troubles: This is the most common reason, especially if you’ve recently changed your password or have more than one account.
  2. Broken user profile: Sometimes, your user profile gets messed up, making Outlook not open right.
  3. Windows registry issues: Certain registry keys for Office 365 might mess up its smooth running. If these keys are broken or wrong, it can cause the error.
  4. Other software getting in the way: Sometimes, other software, like security apps, can mess with Office 365 and cause problems.
  5. Server issues: If you’re using Outlook on a server, some server-specific problems might cause the error.

Also see: How to Check Office 365 User License Using PowerShell

How to fix the Microsoft Office 365 Outlook “Something went wrong [1001]” error

Step 1: Close all Microsoft 365 applications

First, make sure to close all Microsoft 365 apps like Outlook, Word, and others. This makes sure any fixes you do work properly.

  1. Save any work you haven’t saved to avoid losing it.
  2. Go to each open Microsoft 365 app.
  3. Click the X at the top right or go to File > Exit to close the app.

Close all Microsoft 365 applications

Step 2: Sign out of your Microsoft account from any 365 app

Next, open one of the 365 apps and sign out of your Microsoft account. This is needed for the next steps.

  1. Open a Microsoft 365 app, like Word.
  2. Go to File > Account.
  3. Click Sign Out under “User Information”.Sign out of your Microsoft account from any 365 app
  4. Follow any prompts to sign out completely.

After signing out, restart your computer to make sure all changes are applied.

Step 3: Delete “IdentityCache” and “OneAuth” folders

Corrupted cache files might be causing the Outlook 1001 error. By going to a certain directory, you can delete the IdentityCache and OneAuth folders that store cache files for Microsoft 365.

  1. Press Windows key + E to open File Explorer.
  2. Go to C:\Users\<username>\AppData\Local\Microsoft, and replace <username> with your actual username.
  3. Find the IdentityCache and OneAuth folders.
  4. Right-click on each folder and choose Delete.
  5. Follow any prompts to delete the folders.

Microsoft 365 Outlook 1001 Error

Step 3: Clear cached credentials

Old or broken cached login info can cause login problems. Getting rid of these cached credentials can fix these issues, letting you start fresh when logging back into Microsoft 365 apps.

  1. Press Windows key + R to open Run.
  2. Type control and hit Enter to open Control Panel.
  3. Set the view to Small icons and click on Credential Manager.Credential Manager Windows 11
  4. Under Windows Credentials, find any Microsoft or Office entries.
  5. Click on each entry and choose Remove or Delete. Delete Microsoft Office 365 Credentials cache in Windows 11
  6. Follow any prompts during the removal process.

After doing these steps, restart your computer again to make sure the changes work and to prepare for a fresh login to Microsoft 365 apps.

Step 5: Locating and deleting specific files

Now, you’ll need to delete a folder called Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy which might be causing the Outlook 1001 error. You’ll need admin access for this step. Here’s what to do:

  1. Log off your current user profile on your computer.
  2. Login as an administrator because you need special permissions to delete certain files.
  3. Open Windows Explorer and go to:

    Note: Replace <username> with the actual username.

  4. Find and delete the folder named:

    Resolving Microsoft 365 1001 Error for Outlook

  5. After deleting the folder, log off the admin account and log back in with the user’s account.

Step 6: Deleting the Outlook profile

This step is important but be careful:

  1. Warning: Make sure you don’t have any local accounts in Outlook. Deleting the Outlook profile will remove all data. Back up important data first.
  2. Go to Control Panel.
  3. Click on Mail (Microsoft Outlook).How to open Mail (Microsoft Outlook) 32-bit in Windows 11
  4. A window titled “Mail Setup – Outlook” will pop up. Click on Show Profiles….
  5. You’ll see all the profiles on your computer. Select the one named Outlook.
  6. Click Remove to delete this profile. Follow any prompts.Fix Outlook 1001 Error

Step 7: Re-login using word

After doing the above:

  1. Open Microsoft Word.
  2. Login with your email and password.
  3. Complete your 2FA (Two-Factor Authentication). You should be able to log in smoothly.

Step 8: Setting up Outlook profile again

After the previous steps:

  1. Open Microsoft Outlook.
  2. Follow the steps to set up your Outlook email profile again.
  3. Once done, Outlook should work fine.

Related resource: How to Get Outlook to Open Links in Chrome on Windows 11/10

Alternate solution: Fixing the Outlook 1001 login error through Registry

Some users have found another way to fix this by changing the Windows registry. But be careful, messing up the registry can cause big problems. Always back up your system or the registry before you make any changes.

  1. Start by opening the Registry Editor:
    • Press Win + R, type “regedit“, and hit Enter.Open Registry Editor
  2. Then, find and delete a specific registry key:
    • In Registry Editor, go to:
    • Right-click the Identities key and choose Delete.

    Outlook Something went wrong 1001 Error

  3. Finally, restart your computer:
    • After deleting, close the Registry Editor and restart your computer.
  4. Check if the problem is gone:
    • Try logging into the affected app or service to see if the issue is fixed.

If these steps don’t work, you might need to call Microsoft Support or think about resetting the user profile. Always be careful and make sure you have backups before you change your system a lot.

Final words

Most of the time, the Microsoft 365 Outlook “Something went wrong” 1001 login error is because of a broken user profile or old cached login info. Fixing these usually solves the problem. Be careful when trying solutions, make sure you have backups, and if you’re unsure, it’s always good to get help from a professional.

Nyau Wai Hoe
Nyau Wai Hoe is the Founder and Chief Editor of With a degree in software engineering and over 12 years of experience in the tech support industry, Nyau has established himself as an expert in the field, with a primary focus on the Microsoft Windows operating system. As a tech enthusiast, he loves exploring new technologies and leveraging them to solve real-life problems.

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