External backup Hardrive Full but exceeds C drive file size

  tmr 12:22 23 May 2013

My External 500Gb hard drive used for back up is shown as full but my 1000Gb 'C' drive on the Computer shows under 100Gb used in the property window. The total of individual files on the hardrive add up to under 200Gb when viewed in Explorer. What is using the capacity of the external drive?

  john bunyan 13:04 23 May 2013

I find Treesize (free) will tell you .It is fairly easy to use, just click on the drive then expand each folder.


  Chronos the 2nd 14:04 23 May 2013

I would suggest that you are creating a fresh back-up rather than an incremental backup which only adds changes to files. Delete all your old backups and change your back-up setting to incremental.

  john bunyan 15:40 23 May 2013

For data back up I would use Freefilesynch in Mirror image mode. Then copy from left to right and the files will add/ delete as needed.


  tmr 15:40 23 May 2013

Thanks for suggestions I will follow these up.

  john bunyan 16:06 23 May 2013

BTW my suggestion re freefilesynch refers only to data. I have my system partitioned to 100 Gog for OS and programmes, and use Acronis True image to do images which work out at about 40 gig each I keep the latest two (non incremental) then ditch the oldest one when I do a new one. I use Freefilesynch in mirror image mode for the data partition. If there is stuff to keep long term I keep it on yet another drive and even on DVD

  wee eddie 20:44 23 May 2013

It occurs to me, I'm not an expert, that if you are making a Mirror Image of the Drive, as opposes to a Data Back-up, then it would be impossible to mirror a 1Tb drive onto a 500Gb Drive

  john bunyan 22:35 23 May 2013

wee eddie

" it would be impossible to mirror a 1Tb drive onto a 500Gb Drive"

If full, yes. But tmr said only 200gig was actually in use, so the mirror copy would be the same. An ATI image (not so easy to access and MUCH slower), would be smaller by compression.

If one is an avid video user a 1Tb or more drive may be good, but I have found 500 gig quite enough. I would rather have several spare 500 gig drives for my purposes than 1TB or higher.

  lotvic 22:57 23 May 2013

I suggest in Windows Explorer, Folder Options, View, you enable 'View Hidden Files and Folders'

You have not said which Op Sys you are using or what program/method you use to make a backup.

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