@MilesAfton Ah. If it’s Windows 10 user account control, then it makes sense. We actually have a guide to minimize the effect of Windows 10 security permissions, because there has been rare cases where the operating system can actively damage files by blocking execution of the program during the file saving procedure.
While this will not recover your damaged files, it should fix the first error and help prevent the second (though it is not a replacement for creating extra backup copies manually)