Hi @Clemens Fischer ,
Welcome to Microsoft Q&A!
Does it occur in all projects or specific project?
As you said, you changed the Windows SDKs before. Can you install the Windows 11 SDK (10.0.22621.0) via Visual Studio Installer?
Then, run VS as administrator and change the Windows SDK Version in project property to the latest version.
Besides, the crtdbg.h should be located at C:\Program Files (x86)\Windows Kits\10\Include\10.0.22621.0\ucrt.
If you find the crtdbg.h on a different path, please copy the directory path where the crtdbg.h is located.
Then, manually add the path into Include Directories and rebuild your project.
Sincerely,
Anna
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