Are you trying to work on the company file hosted over the server, and QB is set to run on single-user mode? Then, surely, you will get QuickBooks Error 80040408 message on the top of your desktop screen. We have noted all the important details in the blog with its solutions, so follow till the end. If you feel unease while implementing any of the troubleshooting solutions listed in this article, please call +1 855.738.0359 to contact a certified QuickBooks expert to help you resolve the issue.