The 4.0.3 update requires base .NET Framework 4.0. Download the standalone installer from Microsoft (still hosted officially: dotNetFx40_Full_x86_x64.exe ). Install it and restart.

However, if your application explicitly checks for the presence of version 4.0.3 (often via a hard-coded registry key), you may encounter an error saying “.NET Framework 4.0.3 is required.” In that case, you have two solutions:

Introduction