I know this is old, but...
I've read the entire thread, and I noticed that there is "one small detail" which was omitted. First, let me say that all of you are basically right... those of you who say that the RB displays the total size with a few or with many files, that's true; those of you who say it doesn't, it is also true, but I have found it happens under one circumstance, when there are folders that have been deleted. When folders are deleted, the RB displays only the modified date range. In previous Windows versions one could select all the files and folders and press Alt+Enter, or right-click >> Properties, to obtain a total size of the contents of the RB. The only way I can obtain the total size is to look at the properties of the $Recycle.Bin folder on the hard drive from where the files were deleted--this happens if you have a USB hard drive connected and deleted files from it.
Before anyone gets ants in his or her pants, let me explain:
We are talking about two things here, the Recycle Bin (RB) and the $Recycle.Bin ($R.B) folder in the root of each drive.
If you open the RB from the Desktop icon, it will display all, or almost all
eek: Don't fret, explanation to "almost all" is coming right up.), the files deleted from all drives, if there is more than one connected at the time.
If you open the $R.B in Windows Explorer, you will find at least one S-1-5-... folder. Normally you will find two or more on drives that have been disconnected, like USB drives, before the RB was emptied.
Since deleted files are not moved to the C drive when they're deleted from second hard drive, Slave or USB, they remain in their "host" drive. If you DISconnect the 2nd drive before emptying the RB, those files will remain in that drive's $R.B folder, and will NOT be taken into account the next time you connect such drive, therefore, the "almost all" above.
Why not, you ask? Because Windows creates a new S-1-5-... folder each time the external drive is reconnected, and the old S-1-5... folders become "dead files & folders", noticeable to us only when there is a large discrepancy (probably in 10's of GB, at least) between the free space + used space and the total drive space (and the RB is "empty"...
).
If you go into the $R.B folder and you see two or more S-1-5-... folders, you can delete all but the one with the current date. Then, empty the RB and the totals (free+used=total capacity) should now match.
All this being said, Windows 7's Recycle Bin still does NOT display the total size of its contents, if folders have been deleted.
