If you've had trouble signing into your Outlook.com account Microsoft has a workaround available while they work on a permanent fix. The bug can occur in one of two ways. Microsoft explained how the issue occurs below.
You are prompted to sign into Outlook for your Outlook.com account and receive the error dialog below.
Or, you already have your Outlook.com account added in the Outlook Profile, but "Need Password" is displayed on the Status Bar. When you attempt to sign in with your Outlook.com account you receive the error dialog below.
"You can't sign in here with a personal account. Use your work or school account instead."
To work around the issue Microsoft suggests turning off Support Diagnostics which turns off the ability to submit support tickets from inside the app using the Help Menu and Contact Support. The bug impacts the way the app authenticates for support. You can follow these instructions for editing the registry to disable support diagnostics in Outlook.
Below is how the registry key should appear in the Registry Editor once it's been edited.
Image Via Microsoft