Are you by chance using Internet Explorer 11? If you have "Active X Filtering enabled" this will cause this to occur?
No, happens with all browsers on all three of our home computers, on which Mcafee is installed on all three.
When you manually go to install updates for (Adobe) Flash Player for instance. It stipulates that you may have to (Temporarily) disable your Ant-Virus. (Which I am always hesitant to do) Having said this...I never have any issues Downloading/Installing such? And I leave my RTS on.
Do you have Your (Universal Plug and Play) checked in McAfee?
Also, you can open your McAfee Firewall,and temporarily (Turn Off ) Netguard to install your update.I advise to turn it back on afterwards.
In addition, check to see if the above mentioned programs have (Permission) to run.
Just one more thought, It may be that you need to check your (Global Security Settings) with-in Adobe itself?
All the Best,