There are various troubleshooting methods for QuickBooks error 6190 and 816; one of the most common ones has been mentioned below.
Solution: Troubleshoot the Mismatch to Resolve Error 6190 816
First, head to the location of your QB company folder and look for the Transaction folder.
Note that the QB company folder and the transaction folder can have the same name, but their extensions might be different.
You will also have to identify the Two files by their extensions, then right-click the Company files and hit on the Rename option to change the name.
Make sure to avoid changing the extension of the file and change the Transaction file name as well.