So I've been using TM for years now, it backups to my external (1TB) drive. said drive is only there to house my TM. it has been virtually full for months, but ive never had any trouble with it. I assume its been doing as it is supposed to deleting the oldest backups and adding newer ones. since installing ML however I've been getting this error message, all the time. At first I just ignored it assuming it would fix itself and just hit ok, but the problem seems to persist and I don't know what is wrong or what I can do to fix it. TM doesn't really offer all that many options to mess up and trying to find suitable answers online has proven fruitless so far. To add a bit more information here are the settings that are currently set. I haven't fiddled with any preferences TM related since originally setting it up. any ideas? Others have suggesting just reseting it but surely that cannot be the desired answer, as i do sometimes go back in time to get a file that has been deleted or changed.