I've the same issue with faile to install VSE patch 7. But for me it make Win-7 hang after logon to OS. I need to boot to Safemode and disable "mfevtp" services (McAfee Validate Trusted Protection services) then reboot to normal and import "Symantec Class 3 Secure Server CA – G4" by manual to OS.
I open the service requests to McAfee but it still not get any contact from McAfee. so sad......:(
We have decided to deploy the VeriSign G5 certificate through GPO and this has resolved the issue. No more Patch 7 installation failures so far.
I found some of our clients not success to start the "mfevtp" service due to lag of VeriSign G5 certificate installed.
After installed VeriSign G5 certificate the "mfevtp" can success started but performance of clients very slow and sometime not response.
I found the error in Windows event viewer related to CAPI error code 4701.
In Microsoft it has KB2328240 to fixed this error message. https://support.microsoft.com/en-us/kb/2328240
Then install this hotfix from Microsoft the system is back to normal operate and working fine.