Exchange restores are much larger than expected

Hi gurus,

I have an issue restore Exchange Information Store and transaction logs.

Master/Media and client running 7.5.0.7 on Windows 2008 R2

Exchange is 2010 running on Windows2008 R2

I select the Full Exchange backup for the Information Store -  size is 361539480 kb (as reported in NetBackup BAR window)

I select multiple transaction log backups - total size is  3GB

I have a 600GB drive to restore the files to - dedicated to exchange restores and empty.

Restore continues to fail - Restore size reported in Activity Monitor is over 1TB.

Does anybody know why this is occurring?

Thank you.