I assume this should have been tagged on as an answer to https://community.mcafee.com/message/308173#308173 - maybe I'm wrong.
Only you know if the GoToAssist crashed - but if you actually connected with support then it didn't but simply created errors.
Contact them again and insist on escalation of you think there's an ongoing problem.
You mention AVG, I hope you don't/didn't have it installed at the same time as McAfee as they will clash and cause all kinds of issues.
Before contacting Technical Support again ensure that your system is totally up to date, including ALL browsers and their add-ons and make sure you have no software installed that could be deemed as competitive.
If you are now using AVG exclusively, then there's not much point in pursuing the matter.
BTW I didn't mark this thread as assumed answered in case you are wondering about that.
However because it was marked thus, I almost missed it completely.