For anyone who has the same issue I have resolved this error:

 

It was nt occuring for admins, so narrowed it down to a group policy.

 

Our software restrictions policy.

 

This stated for staff/students:

 

User Configuration
Policies
Windows Settings
Security Settings
Software Restriction Policies/Additional Rules
Path Rules

 

Unrestricted areas:
%HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRoot%

 

%HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Cur rentVersion\ProgramFilesDir (x86)%

 

%HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Cur rentVersion\ProgramFilesDir%

 

However it was not until I also added in:
C:\Program Files\

 

That the Quicktime error stopped...