Bug in Delphi 10.3 Rio / C++Builder 10.3 ISO affects TMS installers

We had detected that on some machines here there was an erratic setting in the RSVARS.BAT file in the \bin subfolder for the installed Delphi 10.3 Rio / C++Builder 10.3. It concerns the setting for .NET FrameworkDir:

@SET FrameworkDir=C:\Windows\Microsoft.NET\Framework\v4.5

This variable is critical to set the path where to find the .NET MSBUILD tool. This setting that is in RSVARS.BAT is not correct as this directory is not used for the Microsoft .NET framework v4.5. For some reason, Microsoft decided to deploy the Microsoft .NET framework v4.5 in the folder C:\Windows\Microsoft.NET\Framework\v4.0.30319. So, the correct setting in RSVARS.BAT should be:

@SET FrameworkDir=C:\Windows\Microsoft.NET\Framework\v4.0.30319

We had similar problem reports from several customers and we have been in touch with Embarcadero. We got confirmation from Marco Cantu that this issue is only for the ISO based installs of Delphi 10.3 Rio, C++Builder 10.3 Rio and RAD Studio 10.3 Rio.

So, until a solution comes from Embarcadero, we recommend to edit: C:\Program Files (x86)\EmbarcaderoStudio\20.0\bin\RSVARS.BAT and replace the erratic FrameworkDir setting by the correct one.
After patching this, our installers will be able to invoke the MSBUILD tool to build our component package files.

The developers having installed Delphi 10.3 Rio, C++Builder 10.3 Rio and RAD Studio 10.3 Rio via the web installer are not affected.