Sometimes when you try to open your company file on QuickBooks desktop you see an error code on your screen. QuickBooks error code 6000 is composed of series of errors that are caused by various factors as listed below: • QuickBooks TLG file is corrupted • Issue with QuickBooks installation file • Some firewall or antivirus is interfering with the connection. • There are multiple users logged into the same file at the same time. • Incorrect network configuration. All these causes can lead to QuickBooks error 6000 on your QB desktop app. If you wish to fix the error code and use your QuickBooks without any more trouble, then work on these causes one by one until your problem is resolved.