Member Avatar for Waterdragon900
Waterdragon900 5 Newbie Poster

We use Microsoft Online Services Sign in Tool to allow Outlook to access Microsoft's BPOS online Exhange and Sharepoint services. I recently had a user reporting that the Sign in tool was reporting "incorrect username or password" even though the credentials were correct.
The solution turned out to be simply un-installing and re-installing the Sign in Tool.
I hope this may be helpful to others facing the same problem.

  • 1 Contributor
  • 0 Replies
  • 229 Views
jingda commented: Very helful +5

Dani AI

Generated

As reported on April 20, 2011, a broken sign-in flow with the Microsoft Online Services Sign‑in Tool can look like an "incorrect username or password" error even when the credentials are valid. Reinstalling the client often clears the symptom, but the underlying causes are usually a stale credential/token cache, a version mismatch, or a local profile/service problem. The checklist below gives targeted, low-risk steps to find the root cause and reduce the chance you have to repeat the reinstall.

  • Verify the account outside Outlook first (webmail/portal) to rule out a server-side password issue.
  • Clear stored credentials: Control Panel -> Credential Manager -> Windows Credentials and remove any entries that reference your Office/Exchange/tenant or Microsoft Online.
  • Restart the sign-in helper: open Services (services.msc), locate the Microsoft Online Services sign-in service if present, restart it, then try again.
  • Check Event Viewer (Application and System) for time-stamped errors when the sign-in fails. Those messages often point to the exact failure (network, TLS, token, permission).
  • Create a new Outlook profile to rule out a corrupted profile or cached profile token.

If you proceed with a reinstall, do it cleanly: uninstall the Sign‑in Tool from Programs and Features, reboot, and then install the sign-in client that matches your Office/Outlook bitness (32-bit vs 64-bit). Before deleting files or editing the registry, create a system restore point and, if the machine is domain-managed, coordinate with IT.

For persistent failures, enable Outlook logging (File > Options > Advanced > Enable troubleshooting logging), collect Event Viewer logs, and use network/diagnostic tools (or Microsoft connectivity checks) to look for TLS or proxy issues. If logs are inconclusive, gather them and open a support case so the service team can trace the authentication flow.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.