Capacities not adding up

Hi, I have a MacBook Pro 10.5.8. and am new to Mac.

My hard drive capacity states 185G of which 133G has been taken by "Users" leaving 30G available.

The capacity of my user drive is 372G and apparently there is 31G available - indicating 341G used.

Yet when I add up the used space in the folders within the drive, I have only used 154G.

Am I missing something? (pardon the pun). My gut feeling is that I haven't used this space.

Any ideas on how to trace this mystery loss of disc space?

Thanks
Rogco

 

Thanks - I ran Disc Inventory which identified a user "sparcebundle" folder (sparse disc image bundle) that seems to duplicate 133G.
Can this be deleted or is it important?