Thanks, I'll check explicitly for the combination of NSCocoaErrorDomain and NSFileReadNoSuchFileError then. For anyone ending up in this thread, note that NSFileNoSuchFileError is not the same error as what's being reported by checkResourceIsReachableAndReturnError. The error is: Domain=NSCocoaErrorDomain Code=260 "The file “write-single-file.txt” couldn’t be opened because there is no such file." UserInfo={NSURL=file:///Users/torarne/write-single-file.txt, NSFilePath=/Users/torarne/write-single-file.txt, NSUnderlyingError=0xa83590c90 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}