Strategy Informer  

Before downloading anything, if you have Windows 7 or Vista, then you WILL NOT be able to install the mod if the base game is installed in the Program Files directory. You must copy your game folder to a directory outside of Program Files. Both of those OSs have security "features" that undo changes to any folders inside of Program Files, and moving the game's folder out of that directory will prevent any install problems.
Download the appropriate version, and the hotfix.rar, if there is any. Links to a hotfix will be below the download link.(If you want the graphics too, then download the Graphical Supplement near the bottom of this post as well!)
Find your '\Hearts of Iron 3\mod' folder!
If you have a previous installation, you will need to delete that. Remove the '\HoI3\mod\HPP' folder and the '\HoI3\mod\HPP.mod' file! (If you didn't have a previous installation, then you obviously don't need to do this.)
Unrar the files! (The core files and any possible hotfixes go to the '\Hearts of Iron 3\mod' folder and the graphics rar should be unrar-ed to the '\Hearts of Iron 3\' folder. If everything goes well, it shouldn't need to overwrite anything there, it only adds new files.)
Run the mod with the launcher, select 'Historical Plausibility Project' in the "Select mod to play" list, hit "Start HoI3", and let it build up the cache. This step will take several minutes.
SF Version 2.0 and FtM versions ONLY!! Quit, copy the contents of '\HoI3\mod\HPP\map\cache' to '\HoI3\map\cache', overwriting everything there. Failure to complete this step will result in purple textures on the map! If you're using a version before 2.0 then skip this step.
As of version 1.9, optional colored HQ counters (the same ones used in ICE) are now included in the mod files as the file "coloured_hqs.rar". To use them, unrar the .rar file in the mod folder and overwrite when prompted
Start the mod again.
Have fun! (Or at least help me fix the bug that ruined your afternoon by reporting it here...)


NOTE: If you are having install problems, make sure you followed the instructions above. If you did everything the instructions above said to do, then check out the Tech Help section of the FAQ Sticky for more help. Instructions for Steam users that do not have Windows Vista or 7 are listed below.

Note to Mac users: The Mac version of the base game has problems recreating the map cache. If you download any mod that changes the map you'll see texture errors since for some reason Macs can't rebuild the cache correctly. The final SF and the FtM alpha versions make changes to the map and may result in ugly purple textures on the map. Here's how tommylotto managed to get the HPP map to show up using FtM:

1) Install the HPP as directed above, but don't start the mod.
2) Copy your entire VANILLA map folder to a backup location.
3) Until patch 3.06 comes out, you'll need to download the CMP: http://forum.paradoxplaza.com/forum/...ty-Map-Project. Unless you want to use the CMP's map for the base game, all you need from it is the map folder. Since 3.06 is in open beta you can use the map there.
4) Here's where things get tricky. You need to first replace the CMP's version of the file region.txt in the map folder with the HPP's version.
5) Next go into you cache folder and delete every file in it. Keep the folders intact; you only want to delete what's in them.
6) Start up the VANILLA game. The map cache should be rebuilt, which will take a while. If everything worked correctly, then when you start up the game as any country there shouldn't be any purple spots on the map.
7) If the map is purple-free, then exit the game. Copy your entire vanilla map folder over the HPP's map folder.
8) Delete your vanilla map folder if you don't want to use the CMP's map, and replace it with the backup you made in step 2.
9) You should now be able to select the mod in the launcher and play it without any map problems.


Instructions for Steam users:

If you want to choose between vanilla and the HPP using the game's launcher:

1) Install the mod using the first four bullets above
2) Navigate to the game's folder. It should be in .../steam/steamapps/common/hearts of iron 3
3) Make a shortcut of hoi3.exe on your desktop
4) Start the launcher by clicking on the shortcut
5) In the bottom-middle you should see a drop-down box that says Default. Change that to the HPP
6) Start the game by clicking the Start HOI3 button
7) *HPP 2.0 ONLY: the game should've created a new map cache. Go back to the game's folder mentioned in step 2, find the folder named "map", and delete the folder named "cache" inside the map folder. Then, go to mod/HPP/map and copy that cache folder into the vanilla map folder. You're basically replacing the old cache with the new one.
8) *HPP 2.0 ONLY: After replacing the old cache with the new one, restart the game. Failure to replace the cache will result in ugly purple blobs on the map.

If you want to launch the mod using Steam:

1) Install the mod using the first four bullets above
2) Go to the Library tab in Steam
3) Right click Hearts of Iron III and choose "properties"
4) Click the "Set Launch Options" button
5) Enter the following into the space, then press OK: -mod HPP
6) Start the game
7) *HPP 2.0 ONLY: the game should've created a new map cache. Go back to the game's folder mentioned earlier, find the folder named "map", and delete the folder named "cache" inside the map folder. Then, go to mod/HPP/map and copy that cache folder into the vanilla map folder. You're basically replacing the old cache with the new one.
8) *HPP 2.0 ONLY: After replacing the old cache with the new one, restart the game. Failure to replace the cache will result in ugly purple blobs on the map.
!! In order to use a different mod in your mod folder or go back to vanilla, you will need to undo step 5 and make the text box be blank !!