Nexus 9 help. Constant optimising app screen. Any ideas?

[AC Question]

Hello. So I for home 2 days ago to see my nexus 9 turned off. Presumed battery dead, I charged it and powered on. It appears some software updates had occcured. Now when I turn the device on it constantly days optimsing apps. It gets to 105 out of 105 and crashes. Restarts the process in a constant loop.
Any ideas would be much appreciated. Does anyone have a similar problem?
Thanks
Toby