License Install Failed For License Type: 1 Result Code: 0xc03f6601 Jun 2026

Restart your PC and try activating Office again.

Then, run this to clear the remaining KMS license information from the registry: Restart your PC and try activating Office again

: Failure to upgrade Windows Pro to Enterprise because the device isn't properly synced with a Microsoft 365 license. It’s almost always a from a previous installation

“License install failed for license type: 1 result code: 0xc03f6601” Restart your PC and try activating Office again

Error 0xc03f6601 is frustrating but rarely means your license is invalid. It’s almost always a from a previous installation. The Microsoft SaRA tool or manual removal of the licensing token store resolves it in most cases. If you’re in a corporate environment, contact your IT admin — they may need to reactivate your KMS host or assign a new MAK key.

, especially during subscription-based activations like Windows Enterprise. Common Causes Subscription Activation Lag