How to delete old corrupted backups not showing up in Acronis? Can you delete these from Windows Explorer?

Hi everyone,

On our system, we have run out of space on our D: where we keep our backups stored as no one was performing maintenance. Looking through, I noticed several backups would give the error "cannot continue the operation as either the backup is corrupted or it is being used by another process".

Most of these backups are old so I doubt there are being used by another process, so they must be corrupted and I have no use for them so I would like to remove them to free up space as we schedule new backups to be created every 2 weeks and cannot right now without the disk space. 

I read that you should only delete backups from Acronis or it will mess up the scheduling, however none of the corrupted files show up in Acronis, only in Windows Explorer. I was wondering if it is safe to remove the corrupted filed directly from the D: or will this cause issues? And if it does cause issues, can you fix it relatively easily? Or do the files need to somehow be forced to be recognized in Acronis?

Thanks