Powerful Methods to Overcome the QuickBooks Error 6123 The QuickBooks error 6123, 0 error occurs when users attempt to open their company file, update or upgrade, or restore their file in QuickBooks. The error may also occur during backup operations. Recently, many application users have reported experiencing this error within the user community. Some users faced the error message “connection to the QB company file has been lost,” while updating or upgrading their QBDT. Others encountered it while backing up the company pop-up error message on the screen, saying, “Error: -6123,0. We’re sorry, but QuickBooks can’t open your company file.” https://www.apsense.com/article/875733-powerful-methods-to-overcome-the-quickbooks-error-6123.html