QuickBooks Error Code 6000 Take a look at the different solutions to solve QB error 6000. Restoring a backup of the files is an important way. The next way is to configure your anti-virus software and firewall by opening a QB Database Manager. Renaming .TLGand.ND files and changing the location of the company file (the files which are not opening properly and due to which the error appears on the screen) is also a listed way to fix the error. It is a widely used solution that has been helping individuals and companies successfully. But sometimes these solutions don’t help all. If you are also among them, we can direct you in the right direction.