To fix QuickBooks error 1603 , you will need to work upon troubleshooting the Microsoft .NET framework for damaged Microsoft Windows installer. The first step is to close all the programs on your computer, move your mouse cursor on the start menu and click over it. Now open the control panel on your computer and visit the programs and features . After that, click uninstall a program button and then select Turn Windows features on or off . Now check for the ". NET " framework on the list and checkmark against the file with the name ". NET"framework. Then click Ok and then restart your PC to save the changes.