Thanks for sharing an update with us, @John_K, and @Kershinator.

Allow me to chime in and provide additional insights on how to isolate this issue.

You can work with multiple versions of QuickBooks Desktop (QBDT) in multi-user mode. However, accessing the same company file on the same server isn't feasible. You'll need to run the same version of QBDT to access the file.

Let's say the file is from QBDT 2022, then you're using a recent version of QBDT. Though they are on the same server, accessing the file isn't possible. You'll have to use the same version to open it. This is because QuickBooks creates a new Windows user for each version of Database Server Manger. You can check out this link for the complete details and additional troubleshooting steps: Install QuickBooks Database Server Manager.

Furthermore, you'll want to ensure your recent version of QBDT is up-to-date. This way, they are paired with the QBDT 2022 updates and are feasible when in a multi-user mode once you've installed the 2022 version.

In case you want to learn some tips and tricks in effectively managing your QBDT, you can always visit our QuickBooks Support page for reference.

If you have any other follow-up questions about multi-user in QBDT, please don't hesitate to leave a reply. I'll be here to assist you. Wishing you more success in your business!