Sometimes you will start to log into QuickBooks and you receive the message "User is already logged into the Company file". In some instances the Admin user can log-in, and then force the user's account to log-off using the 'Switch to Single User' functionality in newer versions or using the option to log-off another user via the QuickBooks Messenger in older versions. But in some cases QuickBooks can't seem to actually log-off that user no matter what. Of course, there is also the instance where the already logged-in user is the Admin and in those cases you don't have either of the above referenced solutions available to you.
When this happens you will need to have everyone else log out of QuickBooks and then proceed with ending QuickBooks processes/services on the computer serving as your QuickBooks Server hosting the Company file. To do this:
1) Log-in as the Administrator to the Computer serving as your QuickBooks Server hosting the Company file.
2) Open the Windows 'Control Panel'
3) Select 'Administrative Tools'
4) Choose 'Services'
5) Double-click on the appropriate QuickBooks Database Server for your version (year) of QuickBooks to open the service (for example: QuickBooksDB27 is 2017, and QuickBooks DB28 is 2018)
Windows_Services_QBDBS
6) When the window opens, click the 'Stop' button to shut-down the service. It is critical however that QuickBooks is closed by all users prior to stopping the service.
Windows_Services_Stop_QBDBS28
7) Windows will display a Service Control window advising you that it is attempting to stop the service.
Windows_Services_Service-control_Stopping
The window will close upon completion of the task and you will be back at the previous service window. The service status should indicate that the service is Stopped (as shown below in the Blue box).
Windows_Services_QBDBS28_Stopped
8) Wait approximately 10 seconds, then click the 'Start' button to restart the QuickBooks Database Server.
Windows_Services_Restart_QBDBS-service
9) Windows will once again display a Service Control window advising you that it is attempting to start the service. The window will close upon completion of the task an you will be back at the previous service window. The service status should indicate that the service is Started (as shown in the Blue box below).
Windows_Services_QBDBS_Restarted
10) Close the service window by clicking the 'OK' button (as shown in the Red box above). Then close the Services control panel window and exit the Windows Control Panel.
This process breaks the connection between any QuickBooks User Account and the QuickBooks Database Server (which is the service you stopped and then restarted). As a result, every user should now be able to log back into QuickBooks using their normal log-in accounts and passwords.