If you are installing Sage Accounts and have a different issue with your installation. Error 1921 can happen when you have National Instruments programming running while you are attempting to uninstall it. Update/Reinstall Conflicting Program Essentially, Sage error code 1921 is known as one of the establishment errors looked at by the clients. At the point when you will encounter this sort of error, you will see the accompanying message on your PC screen.