Yu Yuphoria YU5010 is stuck in "Optimize apps # of #" loop. Need to recover data My wife's phone stuck in an "Optimize apps # of #" loop and we are not able to start it. I need to recover few images related to some insurance claim.

I never made any tweaking with the phone except tried to clean the cache files:

Recovery -> Wipe Cache data -> Reboot

Any help will be appreciated. Pointers needed to recover media files.
My daughter's Wileyfox Swift has the same issue...Wileyfox tech support have informed me that it was caused by an incompatibility between a Facebook update and the cyanogen OS. They have sent me files and instructions on force loading OS updates from CM12 to CM13 and from CM13 to Android 7 by forcing reboot with the files on a microSD card. (one reason why I would think twice about buying a device without additional storage). 
 I don't know whether Yu will be equally as accommodating.
Has the phone had USB debugging enabled? If so, then there are several PC apps you might try to get the files you need off. Otherwise, without tech support you stand a good chance that recovering your phone - e.g. using fastboot to flash the apps partition will lose you your user files.