QuickBooks error code 6000 occurs due to multiple reasons like corrupted TLG file, incomplete QuickBooks installation, firewall blocking server connection, etc. Sometimes, the QuickBooks error 6000
also appears on the screen when multiple users are logged in to the same company file. There are several ways through which you can eliminate error 6000 in QuickBooks. Firstly you must try to use the QuickBooks file doctor, rename the files .TNG and .ND and add old after the extension. You may also try to reconfigure the firewall and security software settings. If you are using QuickBooks in multi-user mode then you may try the QuickBooks data file diagnostic tool to identify the data damages in the QuickBooks data file. After that use the QuickBooks connection diagnostic tool and copy the file to the local drive. If you still face QuickBooks error code 6000, then you must try to contact the QuickBooks experts and get their assistance.