The same issue happened to me. I am using a Mac and ensured all the requirements mentioned in the guide were met. However, just before the final check, the screen froze, displaying the message "Hmm... this is unusual" and the "Close and Relaunch" screen. The mouse pointer showed a spinning wheel (this has only happened about three times since I got the laptop). I encountered the same issue with two different proctors. One of the proctors provided me with a case number, and 10 minutes later, I received an email informing me that my exam had been canceled. I tried contacting Pearson technical support, but reaching them has been very difficult... This experience was truly upsetting and disappointing for me.