Resolve QuickBooks Multi-User Mode Not Working Issue with Easiest Solutions It happens that while you are trying to switch from multi-user mode to single-user mode, an error may occur which doesn’t let you continue to change the hosting mode successfully. It happens because the server system signals another system to work up, and for that change to be achieved, you can restart both your computers and the applications. To understand all the causes and the ways to terminate this hosting error, you should read the complete blog carefully.