If you decide to do this, you will have a much harder time un-installing mods, which can be particularily annoying when you want to switch between mods, a mod goes out of date or something went wrong in the installation process.

In the case of mods that over-write files you must re-download said files again after un-installing said mod.

It can sometimes be easier to just re-install the entire game, which will need you to go to the main folder & manually delete any excess files that weren't un-installed by steam.

A potential fix is to back-up the entire vanilla game & any mod-combinations you want for easy mod-switching. This however takes up a lot of space.

Because the game crashes on start-up whenever the mods you have activated exceed 900mb of space. A few graphics mods are enough to hit this limit, which makes this method a necessity for some.

I very strongly recommend that you never try this unless strictly necessary.

1. Assuming you want to install workshop items; go to where you store your Hearts of Iron 4 workshop items. For me this is "C:\Program Files (x86)\Steam\steamapps\workshop\content\394360".

If you want to install a manually downloaded mod, go to where it is located. You hopefully know where it is.


2. Locate & un-pack the mods with the largest file-sizes into a new folder. Typically the largest mods are graphics mods.

To learn what number a workshop item has: Go to the Hearts of Iron 4 workshop on steam, click "your subscribed items" & then click on the mod. The number should be on the upper left of the steam-client.


3. Remove the "descriptor.mod" files, they aren't necessary for this method of installation.


4. Locate your main Hearts of Iron 4 folder, for me it is "C:\Program Files (x86)\Steam\steamapps\common\Hearts of Iron IV".


5. Put the contents of the new folder, the one with the un-packed mods, straight into your main Hearts of Iron 4 folder & over-write anything it asks for.


6. De-activate any mods that you just manually installed using this method when you start the game next time.


It is now done & Hearts of Iron 4 shouldn't crash on start-up, assuming the mods didn't break anything on their own & are compatible with each-other.