To force QuickBooks to open in Single-User Mode, make sure all other users are logged out of the company file, then open QuickBooks Desktop as the Admin user and go to File > Switch to Single-user Mode. If QuickBooks won’t switch, close QuickBooks on all systems, restart the host computer and QuickBooks Database Server Manager, and then reopen the company file directly from the server. You can also disable hosting on workstations by selecting File > Utilities > Stop Hosting Multi-User Access. If the issue still persists, call +1 (302) 205-4658 for professional QuickBooks support to quickly force Single-User Mode and resolve related errors.