WinDirStat is a program available on enginnering lab computers, and Citrix.
This program summarizes sizes of files and folders, making it easy to find large files or folders that may be effecting storage quotas.
Open the apps drive, scroll down and open the "WinDirStat" folder and run windirstat.exe.
When the program is started, a pop-up will appear prompting to choose a drive.
Check the "Individual Drives" option on the left hand side and then in the box, choose your "(Z:)" drive - then click OK .
The window that opens will show you how much of your disk space is being taken up and where.
The top half shows folders and files in order by size and if you click on one, the corresponding visual will be emphasized on the bottom half.
You can delete files by right clicking the desired folder or file and choosing delete to recycle bin (recoverable) or permenently delete (unrecoverable).
To do this you can filter through the top half, searching through each of the directories for files or you can click on the colored boxes in the bottom half which correspond to folders and files in each directory.
Note: The larger the box, the larger the file.
If you would like WinDirStat to use on your home computer - download it here.