Project configurations: Did you set any configurations in your project/project file/project properties like pre-build event/post-build event which may remove the files?.

Extensions: Did you use any extension which may remove/rename files automatically? If so, please try to disable them.VS settings: Reset VS settings by running devenv /ResetSettings command in Developer Command Prompt for Visual Studio 2022 and repair Visual Studio from Visual Studio Installer => More => Repair.vs folder => open VS and try to open GUI.cpp file again. Cache: Close VS => go to solution folder => remove the hidden.If the GUI.cpp file does exist, and it wasn’t renamed, removed or deleted, then please check following: When the issue appears, please right-click your project => Open Folder in File Explorer => confirm that the GUI.cpp file exists => make sure that the file has the same name with the displayed item in VS Solution Explorer => go back to Visual Studio => right-click your project => Unload Project => right-click it again => Reload Project => Build your project => double click the GUI.cpp file and check if it opens without any errors. We may first check and confirm that the error message says correctly or not correctly.

Visual c++ build tools