Troubleshooting internet connection issues, firewall settings, and having mulitple instances of QuickBooks installed on the computer.

This article describes why a connection to the company file may have been lost and how to troubleshoot a resolution.

Network errors such as error -6000, -80: "An error occurred when QuickBooks tried to access the company file," can occur when restoring a QuickBooks company file from a backup, updating a company file, or attempting to open a company file.

A number of issues can cause error -6123, 0: "Connection to the QuickBooks company file has been lost" to occur when opening a company file stored on another computer. Follow the steps to determine what is causing the error and how you can resolve it.