To resolve QuickBooks Error 6190, begin by making sure all users are logged out and that the company file is not open in single-user mode on another system. Update QuickBooks Desktop to the latest version, then locate the company file folder and rename the .TLG (transaction log) file so QuickBooks can recreate it automatically. Check that the company file and the .TLG file are stored in the same folder and that folder permissions allow full access. Running the QuickBooks File Doctor can also help fix file or network issues causing the error. If the error still persists, you can contact QuickBooks support at +1 (302) 205-4658 for expert assistance.