Same mobile and same for me, a bunch of scenarios keep shifting turns, shuffling and happening:
1- Download Starts and Fail due to Internet Connection or Free Space on Device (error code 0X1CANT2REMEMBER)
2- Download Finishes, Preparing to Install Finishes, Installing starts and Fail due to Free Space (same error code)
3- Download Finishes, Preparing to Install Finishes, Installing finishes, and when a restart your device option should appear as usual, it says instead something happened, we'll try to fix this, pleas try again later.
I'm desperate, deleted all my apps that are not allowed by their creators to be moved to SD card, all WP Extras, logged of all my work and study email accounts I have, I need to know the size of that update, I don't wanna reset my phone

HELP US!