when the Quickbooks error 6123, 0 occurs, QuickBooks displays an error message saying, “Error: -1623, 0 We're Sorry, QuickBooks can't open the company file." In addition to running QuickBooks File Doctor and Updating QuickBooks Database Server Manager, users are instructed to perform standard troubleshooting procedures in order to resolve company file errors. In many cases, basic troubleshooting alone isn't enough to fix error codes like 6123, 0; you will need to implement additional troubleshooting in order to resolve the issue.