External Hdd says im using more space than i really am.

I have a Toshiba 1tb that i use to backup personal files, music, all that.
I had the Hdd set for backup but it was using alot of space and i diddnt really care to backup because im smart with my computer. I ended up deleting all the backup files and changing the schedual to never (but i cant find out how to make it not show on the backup thing) all the files are out of the hdd (for backup) so it cleared some amount of gigs. but still im losing 340 gigs to what?

Hi there, i have seen instances in the past where when deleting system/image backups if you delete the top folder/icon it does not always remove the backup data in sub folders unless you manually navigate down through the folders clicking yes to give permission for each folder as you go. If you never ventured inside them you do not have permission to modify so when deleting it leaves most of it behind.

Is there anything else on the drive you still want?
Easiest way is to format the drive which will wipe it clean and recover all free space with no messing around, quick format is really quick, just be sure to remove any data you want to keep before doing this and make sure as 340GB seems a massive amount of space just for backups
Try going to Control Panel>Folder Options>View and ticking the box that says view hidden files and folders and check the drive again

If your not sure or need any more help post back with a snip picture of your maximised disk management window

Start>type "diskmgmt.msc>

Hope this helps

If Pauly's solution does not fix it then consider:

I have seen this happen on my own external drives. What I discovered was that the RECYCLER folder on the external had become detached from the Recycle Bin on my desktop. Files that had been marked for deletion where still taking up real estate on the external even though they were no longer visible in the Recycle Bin for permanent deletion.

Lesson learned: Always empty the Recycle Bin before disconnecting an external drive.

One possible solution:
Use Disk Cleanup. Select your connected external and see if the Recycle Bin shows the missing GBs, and clean them from there.

If that does not solve it, then you could consider a more advanced solution here:
External hard drive has recycle bin--how to access? - CNET Storage Forums
Scroll to the bottom and look for "The Correct Solution" post.

Hope that helps