QuickBooks error 6000 is an error that may occur when you try to open a company file on your PC. It can also arise when you are attempting to restore a previous backup of your files. Furthermore, there could be several reasons for getting QuickBooks error code 6000 on the system screen. You need to find out the various reasons before going for the solutions. Causes of QuickBooks Error -6000 These are the causes of QuickBooks software error 6000 : 1. Might be your firewall is blocking the connection. 2. Corrupted.TLG could also be the reason for the error. 3. The installation file of QuickBooks is corrupted. 4. Maybe the network connection on your PC is wrongly configured. 5. The error may also arise in case you are attempting to restore a backup of your files. Solutions to Fix QuickBooks Error Code 6000 You have to go through the solutions to get rid of QuickBooks Error Code 6000 : Solution 1: Backup of File 1. To begin with, you need to open a co