Happened to me but when entering a match. I got the "syncing account" overlay but could see the life go on behind it, ppl interacting and counter counting, but I couldn't do anything because I had the overlay on top. I had to kill the game.
I also noticed that the "syncing account" between matches takes way longer than expected, to the point of letting me interact when everybody readied up, matchmaker balanced the teams, and the match launched. I guess it has to do with the same issue.
There's an issue somewhere in the connection between you and the various backend servers that Hawken runs on.
Hit F5 and type disconnect and then hit Enter. This resets that connection.
Unfortunately, this only works sometimes, so if you're still having an issue after a few minutes and then another go of disconnecting, you may need to wait a while for whatever issue is on the intervening networks to go away.
Amid, gonna try that next time it happens. Good tip! Thanks a lot!
Edit: happened to me again, tried what Amid said and the game attempts to drop me at the garage but stays stuck in the syncing loop. I'll try to open a support ticket but right now the zendesk doesn't load (maybe it's related?).
Edited by Liederkranz, 19 May 2015 - 07:39 PM.