I think the only correct way to handle failures is to have a single file called ONE_DRIVE_RESTORE_FAILURES.txt at the restore destination root, and in it list t

I think the only correct way to handle failures is to have a single file called ONE_DRIVE_RESTORE_FAILURES.txt at the restore destination root, and in it list the path to every file that failed to download, one path per line. Much harder to miss than individual files with conspicuous names.