2019 MacBook Pro user, they made me download and run chrome to take the exam, last time (July-flex for me) they let me use Firefox. I am not sure if that's even a choice now, so have Chrome as an option just in case!

Happened to me yesterday, (Mac user) First, they didn't inform me that I had to run chrome on my system, then after about 3 techs and 2 proctors I finally got into the test only to be interrupted with the time running that I could not talk to myself (I was able to regain my flow luckily). This is my second test and the first was way smoother. I think that it will get better as they go, but definitely different workers on the other side yesterday.