I found a lot of events with the 3033 ID but the instructions don't tell you want to do with that knowledge,
What is the name and version of the Symantec and Citrix applications you have installed?
Please check those ID 3033 events again. If you select one in the upper pane, the
Details pane will tell you which DLL file it was that was trying to insinuate itself into the browser. Look particularly for events dated both before and after you updated the Symantec software.
You could take the risky course of disabling this layer of protection, but only until you've tracked down the specific cause and eliminated it. If you want to do this, say so and I'll post instructions.
Thinking about all my friends that swear by their Mac systems. :-/
Macs have a similar system, so it's not unlikely that Mac users would face similar problems in similar situations.
[I've been trying to think of an analogy to explain what's happening. This is the best I could come up with, using a topical theme:
Imagine a hospital intensive care unit. In the midst of an epidemic, the hospital's owners decide to impose a new mandatory safety measure to prevent infection: everyone - doctors, nurses, porters, cleaning and maintenance staff - seeking to enter the unit
has to have been health-tested and carry a special badge issued by the owners to say so.
Maintenance of specialist equipment is contracted out to another company. Along comes an older engineer from the contractor to check the equipment. He has been tested, but his employer hasn't issued him with one of the new badges. When he tries to enter
the ICU, klaxons blare and the doors are locked shut.
The engineer poses no risk (because he's clean); the problem only arises because the contractor failed to follow the hospital's instructions about getting badged and the fail-safe protection measures kick in.
Hospital owners - Microsoft
Hospital - Edge
ICU - browser renderer
Contractor - Symantec
Engineer - Old Symantec DLL
Badge - Microsoft certificate
I clearly have too much time on my hands ...]