6000 series errors in QuickBooks are associated with multi-user mode. Users can get the QuickBooks error 6000 80 when they try to open your Company file, but the application fails to access it. It mostly occurs if hosting is active on multiple computers in the network. You can use the QuickBooks Connection Diagnostic tool to fix the error or turn off hosting from all the computers except the one which has the Company file. If you need an expert’s assistance, contact our (844)-932-1139.