If you're still having trouble getting the game to load....

iammistahwolf

For those still having trouble getting the game to load (retail version), do the following using OIV:

Back up your previous/current dlclist and config located in the 'Mods > update > update.rpf > data folder.
Back up your current Mods folder. (yes your dlclist and config will be in there, having them backed up separately will make a later step easier and you should back up your Mods folder anyway)
Go into the updated vanilla portion of the files in OIV and copy both the update.rpf and update.rpf2 files from the 'update' folder to a DIFFERENT FOLDER on your computer (not the same one you used to back up your old dlclist and config so there won't be any confusion). Do Not use 'Show In Mods Folder' in OIV. You'll need an actual copy of both files.
Go back to the 'Mods' folder in OIV and 'REPLACE' both the update.rpf and update.rpf2 folders with the new vanilla ones. (yes, replace them both fully)
Start the game, it should load just fine. When it does, shut it down and go to the next step.
Go back to OIV. Select 'Edit' then take the two copies of the saved dlclist and config from the previous version and 'REPLACE' the vanilla version that came with the update.rpf folder you just put in. Having the two files separate saves you from having to dig them out from your backed up mods file and OIV will accept them easier.
Start the game. Should the game go into infinite loading again, there's something in your dlclist that got broken in the update. Most likely it will be an 'addon vehicle' or 'weapon'. Broken modded interiors tend to crash the game when you get near them after the game loads. To fix the loading issue, go back into OIV select 'edit' and then get your dlclist and remove all lines for your mods while leaving the lines for the game dlc's alone. You'll have to add mod lines (one at a time) and restart the game until you get to the one that causes the 'hang'. If you have a lot of mods...you'll be at it for a while. When you do find the 'hanger', keep doing this (because there's usually more than one) until the game starts with all your remaining mods.

That's it. Good hunting!