What you’re seeing
- Word, Excel, PowerPoint or Outlook keeps showing the Microsoft 365 sign-in window after the password is entered.
- Documents open in read-only mode with a banner saying the product needs to be activated or signed in.
- The sign-in window flashes briefly and closes, or shows a blank white page.
- Signing in works for a day, then the prompts start again.
Common causes
Every environment is different, but these are the causes our engineers find most often:
- Cached Microsoft credentials in the keychain are corrupted or belong to a different account.
- A personal Microsoft account and a work account are both signed in, confusing licensing.
- Conditional Access or MFA policies in Microsoft 365 require a compliant device that the Mac does not satisfy.
- The Office license assigned to the user was changed, removed or exceeded its device limit.
- Old Office versions or leftover license files conflict with the current subscription.
Why it matters
When Office cannot confirm the license, editing is blocked and staff are stuck viewing documents they need to change. Repeated sign-in prompts also make people more likely to enter credentials into a fake page without thinking. If the cause is a security policy mismatch, the user may be unable to access email and files for hours. Across a small team, this kind of loop can mean a lost morning for several people at once.
How AskTechGurus fixes it
Skip the trial and error. A certified engineer works on your actual system, finds the root cause, and fixes it properly.
Tell us what’s happening
Submit a ticket in about two minutes. Paste the error, describe what changed, and pick your tier. No charge to submit.
A certified engineer diagnoses it
A vetted, US-based systems engineer claims your ticket, usually within minutes during business hours, and investigates over a secure remote session you can watch and end at any time.
Fixed and verified with you
The engineer resolves the root cause and confirms with you that it’s working. You don’t just get a workaround, and you get a plain-English summary of what was wrong.
Pay only when it’s resolved
Fixed price from $99, invoiced only after you approve the fix. If it isn’t resolved, you don’t pay.
Frequently asked questions
Is our Microsoft 365 account locked?
Usually not; the account typically works fine on the web, and the issue is with how the Mac stores or presents the sign-in.
Could this affect other staff?
If it stems from a Microsoft 365 policy or license change, other Macs may be affected too, so it is worth looking at the cause rather than just one machine.
What does it cost to fix?
Help starts from $99 for a remote secure session with a certified US engineer, often resolved in a single session, and you pay only when resolved.