QuickBooks Error codes 6189 and 816" signify a problem with the firm file access, possibly caused by network issues, corrupted data files, or mismatched transaction logs. It prevents access to files and must be resolved by troubleshooting procedures such as confirming network connections, resolving conflicts, or restoring backup files. Please give us a call at 1.855.856.0042 if you would want to discuss QuickBooks support in private.