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backup size different from used space

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Hi Friends,

This is probably one of those newbie questions that you get all the time.  But I searched help and read the FAQ.

I just did the first backup of a new computer.  The hard drive's Properties showed that there's 77 gb of used space.  But when I did a full backup, it's only 60 gb.  I even erased the first try, since it was set for incremental instead of full.  But the second backup, set to full, was still just 60 gb.

It just seems like a pretty large discepancy.  Could that be right?

Thanks for your patience  :-)

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Brynn, when you make a backup, one of the settings on the Advanced options page deals with the level of compression to be used which is set to 'Normal' by default.  Normal compression would expect to achieve around 20% reduction in size for the backup data being stored in the .TIB file archive.

If we take 20% of your original 77GB used space, plus also factor in the normal exclusions for the system pagefile, hibernation file and swapfile, then it is easy to achieve the 60GB you are seeing.  Default exclusions also include System Volume Information which were system restore point information is normally stored, but this is likely to be small on a new computer.

Oh ok -- that explains it.  Thank you very much!