Steam Launch PBO Recognition Problem

[armedtoe 1]

When launching via a custom shortcut or directly from the .exe, there are no problems.

However, when launching via the "Play" button on steam, my missions, addons, ect are not picked up by the game.

My missions are located in "D:\Games\SteamLibrary\SteamApps\common\ARMA III Alpha\MPMissions" and the addons are in the "D:\Games\SteamLibrary\SteamApps\common\ARMA III Alpha" folder.

Don't worry about the weird path, it's because I have games on two separate harddrives.

How can I get the game to pick up the missions and addons when launching through steam?

Things tried:

1. Running Steam as Administrator

2. Removing permissions on the items in the folders