The following are the instructions for downloading and installing the diagnostic tool: · Download the QuickBooks Diagnostic Tool from the intuit QuickBooks website and install it on your device. · Save the installation file to your PC after downloading it. · After downloading, the 'QuickBooksInstalltoolv2.exe' file will appear on your screen. · Now, close all other programs currently operating in the system. · Run the 'QuickBooks Install tool v2.exe file' in your system by double-clicking it. · After the diagnosis, restart the system.