1.        “Found File” and “Lost File” tabs, while “Orphan Files” is correctly plural.
2.       Of the three tabs that could have a “select all” checkbox, “Found File” and “Lost File” do, but “Orphan Files” does not.  Why not?
3.       For all these “select all” checkboxes, I suggest it may be misleading to simply select all items on all pages without notification or confirmation dialog.  If I have hundreds of pages of 50 items each, it might be worthwhile to either warn or—perhaps even better—ask if they want to select/deselect all or just the current page.  It may not be immediately obvious how many pages exist, and the user may be tempted to select all after viewing only the current page.
4.       Size and Parts columns in “Found File” is sorting on Character value instead of on numeric value.  In other words, 400 is erroneously sorted to be less than 50 because the “4” character is less than the “5” character.
5.       Not that it’s necessarily needed, but under “Orphan Files” tab, “Parts Found” and “Modified” tabs do not sort.  Note that “Modified” column is sortable in “Found File” tab.
6.       It appears that the “Orphan Files” tab has the same sort problems with “Total Parts” and “Size” that exists in “Found File” tab (see #4).
7.       It appears the “Lost File” (which I cannot fully test because none exist) has some unsortable columns.  I would want to confirm numeric values are sorted on numeric value instead of character value.
8.       In “Directories” tab, there would be benefit to sorting on “Max Node” and “Max Size” columns in addition to “Skew” columns being sortable.
9.       In “Directories” tab, I could see benefit to filtering on “Max Node” to allow easy isolation of the causes of disk usage skew.
10.   In “Directories” tab, the “Skew” and “Skew” columns are not populated.
11.   In “Error/Warning(s)” tab, what is the intended purpose of the “Open” button.  It is active only when one of the items is selected.  It does not appear to do anything.