Some NTFS junction points in Server 2008 are not recognized so SpaceMonger reports the used space twice. Specifically, c:\Users\All Users\Microsoft is junctioned to: c:\ProgramData\Microsoft
None of the other junctions appear to be duplicated, so I'm not sure what is causing this one to be.
Hyper-V stores its images under that structure so it became very obvious.
This also causes problems with the treemap being displayed correctly. I have a 1.5 TB raid set that is 30% free space. The contents under the folder juntioned folder is approx 500MB. Because SpaceMonger thinks it exists in two places it shows that 2/3rds of the map is this structure that should really only be 1/3 of the map.
This is in v2.1.1 build 1553
