This behavior matches a sign-in/account synchronization problem on that desktop rather than a password problem, especially since the same Microsoft account signs in normally on the laptop.
The supported fix is to disconnect the Microsoft account from Windows on the affected desktop, restart, and then connect it again.
Steps:
- Sign in to the desktop using the password path that still works.
- Open Settings > Accounts > Your info.
- Under the Microsoft account section, select Sign in as a local account.
- Select Next.
- Enter the current Microsoft account password or Windows sign-in password when prompted.
- Enter the local account details and complete Sign out and finish.
- Restart the PC.
- After restart, go back to Settings > Accounts > Your info.
- Reconnect the Microsoft account to Windows.
This is intended to clear the account sync state that can cause repeated verification prompts.
If sign-in prompts continue after reconnecting the account, also try these supported checks:
- From the sign-in screen, use I forgot my password or I forgot my PIN if either option appears.
- Restart the device fully. If updates are pending, use Update and restart.
- On the lock screen, confirm the desktop has internet access by selecting the Network icon. If Wi‑Fi is unstable, try Ethernet.
- If the issue appears tied to verification methods, avoid repeated attempts. For temporary blocks, try another verification method, try another network, or wait up to 24 hours before retrying.
If unrequested verification codes are ever received, do not approve or use them unless the sign-in was initiated intentionally.
- User Account Access in Windows | Microsoft Support
- Troubleshoot Problems Signing In to Windows | Microsoft Support
- Troubleshoot Problems Signing In to Windows | Microsoft Support
- Choose a way to sign in dialogue box is blank - Microsoft Q&A
- Troubleshoot verification code issues for work or school accounts | Microsoft Support
- Troubleshoot verification code issues for work or school accounts | Microsoft Support