Hi there, @Ann99. 

Thanks for following along with the thread and sharing your concerns. I'm happy to lend a hand with your error message. 

Often times we can resolve this error message quickly by relaunching QuickBooks with elevated permissions. To do this, you'll need to right-click on the QuickBooks application and choose Run as Administrator. 

However, if the error persists, you can follow the given steps by our user, Sanya. Renaming the .NG and .TLG files are configuration files that allow QuickBooks Desktop to access the company file(s) in a network or in the multi-user mode. Corrupted or damaged .ND or .TLG files can cause errors when opening QuickBooks Desktop. Renaming these files does not cause data loss since these are automatically recreated when you open or scan the company files using QuickBooks Database Server Manager.

Additionally, you can run the File Doctor. This way, you can scan the company file for any potential data damage issues causing the error message. To do this: 

Download and install the QuickBooks Tool Hub and run the File Doctor. See Fix company file and network issues with QuickBooks File Doctor.

Please let me know if you have any questions or concerns. I'm always around to help you out. Have a good one!