Many QuickBooks users around the world have been disturbed by QuickBooks error 6000. It is not a threat, however. It can be resolved easily by running QuickBooks file doctor. Make sure to troubleshoot the error if it has not been resolved. Top Solutions to Resolve QuickBooks Error code 6000 Solution 1: Update QuickBooks Solution 2: Run QuickBooks File Doctor Solution 3: Use ADR to Restore Backup Solution 4: Run QuickBooks Database Server Manager Solution 5: Close all QuickBooks Processes Solution 6: Open a Sample Company File Solution 7: Rename .ND and .TLG files Solution 8- Configure the Firewall