Welcome, and thank you for taking the time to seek out the Community for help. I have a recommendation for you that can help when workstations open the company file in single-user. Every user in QuickBooks has the ability to manually change the file from multi-user mode to single-user, as it is built in by default without a setting to change it. However, the file should stay in the same state that it was when being closed. So if the file was in multi-user mode when closed, it should be the same when reopened. If it's not, the settings for some services and the database manager on the server may need to be tweaked. Here's how:
When working with QuickBooks Desktop in a multi-user mode, QuickBooks services (QuickbooksDBXX and QBCFMonitorService) need to be running on the server. When they're not set up to start automatically, this can cause the file to open in just single user mode when accessed from a workstation. Following the steps below will help you to set them up properly.
Press the Windows key + R to bring up the run box.
Type services.msc, then press Enter.
In the services window, scroll down and look for the QuickBooksDBXX service. Note:XX represents the year of QuickBooks Desktop you are troubleshooting.
Double-click the QuickBooksDBXX service and make sure the Startup Type is set to Automatic and service status is Running or Started.
Click the Log On tab.
Under Log on as: Choose Local System account with Allow service to interact with desktop.
Next, click the Recovery tab.
Select the drop-down menu for First failure, then select Restart the Service. This will automatically restart the QuickBooksDB service if it fails. Do the same for Second failure and Subsequent failures.
Note: The information I've provided can be found under the subsection "Solution 3: Check hosting and services," and then "Verify QuickBooks services."
Once you've made these changes, try opening QuickBooks on your workstations. Like I mentioned before, there's not a way to prevent non-admin users from changing multi-user mode to single-user. However, now if the file was closed in multi-user mode, it should open in the same state. Still, I can see how this would be beneficial, so I'm going to send this feedback to our Product Development team. They consider suggestions like this when developing new features for the program.
Should you have any questions about this or anything else QuickBooks, don't hesitate to seek me out here in the Community. I'm always here to help. Thanks again for reaching out.