In addition to the solutions mentioned earlier, here are some other ways to fix quickbooks error 6190 and 816:

Verify and rebuild the data of the company file.

Copy the company file to a new location, and then try to open it.

Make sure that all users are logged out of the company file, and then try to open it.

Update QuickBooks to the latest version and install the latest updates for Windows.

Try disabling the antivirus or firewall temporarily, and then try to open the company file again.

Check for any issues with the network or server hosting the company file, and address any issues accordingly.

If the error persists, try creating a new user login in Windows and open the company file through that user account.

If none of these solutions work, you may need to contact QuickBooks technical support or a qualified IT professional for further assistance.

You can also fix this error in your:- QuickBooks desktop error 12007