Office Rouge One?!

One of my favorite tickets to troubleshoot...

"Office isn't activated anymore."

You check the licensing, everything looks fine. The user has a valid Microsoft 365 license. Then you notice it...
At some point they signed into Office with their personal Microsoft account instead of their work account. 😑
Now Outlook is confused, OneDrive is pointing somewhere else.
Office says it isn't licensed and everyone's pointing fingers at IT.
The problem wasn't Office, the problem was identity.

One simple way to reduce this is by controlling how users are allowed to sign in to Office:

Open Registry Editor
Go to:
HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\16.0\Common\SignIn
If it doesn’t exist, create WindowsCopilot
Create a DWORD (32-bit) value called:
SignInOptions
Set it to the number you want here are the available values:

SignInOptions = 0
😤 Both organizational and personal Microsoft accounts allowed (Default)

SignInOptions = 1
✅ Only organizational (Work or School) accounts are allowed

SignInOptions = 2
⚠️ Only personal Microsoft accounts are allowed
(Rarely used in business environments)

SignInOptions = 3
✅ No additional accounts can be added to Office

For most business environments, SignInOptions = 1 is the sweet spot.
It allows users to sign into Office with their Microsoft 365 / Entra ID account while preventing personal Microsoft accounts from being added.

Why does this matter?
Because when users start mixing personal and business identities, things get messy. I've seen:
- Office suddenly "lose" its activation
- Personal OneDrive become the default save location
- Documents synced to the wrong account
- Users unable to access company resources
- Hours spent troubleshooting what was really just the wrong account

Business devices should use business identities.
Business applications should use business identities too.
One identity. One tenant. One less support ticket. (Why does this sounds like a nerdy Bob Marley thing?🎸😂)