QuickBooks error 6000 occurs when a user tries but is unable to open any company file. QuickBooks error 6000 appears as an error message with a few extra digits. This is due to the fact that QuickBooks error code 6000 is a collection of errors that prevents the user's system from accessing system files. When attempting to access a system file, you may encounter any of the 6000 error codes. Quickbooks error 6000