I have hosted sites for over 13 years. I went to Bluehost in like 2009 I think, because I needed a simple service, offering me a cheap option for Linux.
This week, at least 5 sites I have hosted there got hit by the white screen of death.
I have fixed all but one- which had deeper issues…but all the rest, turned out to be due to a Bluehost thing.
The default permissions on a critical folder, are set to not write – so an update happening, would hit this folder and not update the files it holds. They will point out I could change the permissions here- but it is not something you do, unless very intentionally directed.
So the WordPress site, set to automatic upgrades, tried to upgrade, and did it, about 9/10ths of the way- but one file in particular on Bluehost, does not update for sure: wp-includes/formatting.php
This makes the whole site white out, and makes it impossible to admin thru WordPress.
I found, if you take the formatting.php file from a clean version of WordPress 4.0 and overwrite the local on your whited-out site (there are no unique identifiers in this file, it is a core wp file), you are gold.
Sometimes, it may be a plugin issue- but in the sites I put back online this week, all of them were on Bluehost, got whitecreened by a WP upgrade to 4.0, and all of them needed this file update.
Happily, after the first one, which took a couple hours to find and fix, this makes it fast and easy. At least to rule it out.
But God- Bluehost can suck it: I am done with these losers. Sorry for steering anyone that way, ever. They made simple muddy, and ruined the things that made them good.