I've just discovered that some of the settings for the project options in the IDE were set to UTF-16LE and this could be why the resource file used an invalid coding. I've changed these to UTF-8 and this seems to have helped with a new project.
This shouldn't cause a problem, moreover you said that it worked for the first compile.
Maybe this is a bug...
I just loaded the \Samples\Add-Ins\BuildVer project into Pelles C 12.00.2 on Windows 11, converted the buildver.rc file from UTF-8 with a BOM to UTF-16LE with a BOM and the IDE crashed on Build ReBuild or Clean.
Bug ? Yes. Pelles C or Windows 11 ? My guess is Windows 11 because frankie said no problem with Windows 10.
I have just finished loading a fresh install of Windows 10 on my old machine.
As above, I loaded the \Samples\Add-Ins\BuildVer project into Pelles C 12.00.2 on Windows 10, converted the buildver.rc file from UTF-8 with a BOM to UTF-16LE with a BOM and the IDE crashed on Build ReBuild or Clean.
frankie and I have had different results. He says O.K. I say not O.K.
What I have learned and intend to do is not use UTF-16LE with a BOM with Pelles C 12.00.2.
Tomorrow I am going to run the same tests with Pelles C 11.
Trust but verify !