After updating Windows, my QuickBooks Desktop suddenly stopped working in multi-user mode. I discovered the Windows Firewall reset its rules, blocking key QuickBooks services. This caused a total disruption to our accounting workflow.

The fix involved manually reconfiguring firewall rules—something that isn’t obvious unless you’re familiar with QuickBooks networking needs. I had to open the required ports, add program exceptions, and ensure that QuickBooks Database Server Manager was running on the server.

Thankfully, Smith from QuickBook SupportNet pointed me to the QuickBooks Tool Hub, which helped diagnose the problem. However, manual steps were still needed to complete the repair.

If you’re experiencing similar issues after a Windows update, check your firewall settings. It may have reverted to default, blocking QuickBooks services. Would love to hear if anyone else had this happen and what worked best for you.