There are a few reasons why software that was previously on the computer systems is no longer permitted: licensing changes occur; newer updates or version may affect functionality of the system; a security risk may present itself.  Here are two examples:

September 19, 2018: “Information Technology Services is removing the SSH Secure Shell client from Mason-owned computers because it is out-of-date and is a security risk.”

August 19, 2016: “Apple recently ended support for the QuickTime player on Windows-based systems. Termination of support presents a security risk, so in response, Information Technology Services (ITS) will also no longer support QuickTime for Windows and will remove it from all Mason-owned equipment.”