What are therse files to compress

[The Old Timer]

I decided to run the disk cleanup utility on my second drive which is used
for video & therefore normally only has large files. It said that I had a
huge amount of unused files & that I should get them compressed. This took
over a half hour to finish. What could these files be? How are they
compressed? Are they taking AVI files & saving them as DV?

 

[Guest]

Compressing files, folders, and programs decreases their size and reduces the
amount of space they use on your volumes or removable storage devices. Volume
compression decreases the amount of space that is used by all of the files
and folders that are stored on that volume. Because of a potential loss of
performance, you may not want to compress some files.

Read more at:
http://support.microsoft.com/default.aspx?scid=kb;en-us;307987