How do I fix Microsoft Installer Error 1603?

balerm · Feb 20, 2021 3:49:07 PM

I can't open turbotax premier 2020 on a Windows 10 laptop with the business edition of Windows 10. On the update page, I get "Microsoft installer error 1603." Even though I manually updated turbotax successfully, turbotax won't open because the update page appears and shows the "microsoft installer error 1603" again. I've tried disabling my antivirus, and that didn't work. I've used turbotax for many years and never had this problem. How do I fix this?