CE-34788-0 Update file cannot be used.

 yes, it will erase all data. It did save game save files I assume to online storage (cloud) which I was able to recover. I've done/tried all 3 options of just trying to re-try the latest update (smaller file via USB. It came close to working once. When it didn't I did just the regular "initialization" which erased everything. Any PSN dlds I had paid for, as long as you can sign into your acct, you can re-dld at no charge. But a few days later, after dld Netflix & one game, during the 2nd game dld/install (from a disc, not an online dld), it bricked again. Always this cycle of "checking system storage">the ps4 cannot start, plug in controller, hit ps button>prompts to dld latest update via USB>safe mode. Just an endless safe mode loop basically. Then I dld the "big" update which is basically re-dld the systems software i assume. Like the initialization, this worked & got it back up. But after a couple game dld/installs it goes down. This last time I had been dld The Witcher for almost 2 days (wifi), leaving it in ready mode. When it finally finished, I put the ps4 into rest mode & when I went to activate the ps4 it went down. Sorry, to answer your question, unfortunately yes it will erase your vids etc if you initialize or re-initilaize. if you can just get the small update to work, pretty sure it won't delete, just update to the latest one. I'm so sorry you're having this trouble also. I'm just out time, games saves, & some loot. It burns me up this is happening to so many people especially with the price of this system. I just got an Ethernet cable so I'm going to reinitialize ONE more time & dld with Ethernet instead of wifi & see if that helps. And get an external HD to dld to so if it happens again, i still have my stuff. I'm almost positive my HD is bad. No idea how that happened. After this im either buying a ps4 & switching out hds or saying good-bye to Sony. Good luck with everything. I've heard before you try initializing, boot in safe mode (hold down power button til it beeps twice) & try all options down the list one at a time before you resort to either initialization option.