https://psteamcommunity.yuanyoumao.com/app/1874880/discussions/1/594022439299650480/

solution:

So my problem was actually that I had the game installed previously and had a launch argument setting the addons folder to a place where it wasn't. If you are reinstalling the game you may want to check properties in steam to make sure you don't have any thing in the launch options
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Copy and pasted solution that worked for me

I figured it out, it was windows defender being too defending, decided to block access to the documents folder for mods and such

引用自 Fishankles：

Every time i try to load into a community server it just refuses to downloads the mods and says it fails, I dont have a arma addons folder in my documents and im not sure whats going on anymore.

I don't like my settings and mods buried deep in the user folder the way they do it. I don't even like it on my C: drive. This switch in the launch option field of stable and experimental will relocate them and also keeps stable and experimental separated. -profile "E:\Reforger Profiles\Stable" and -profile "E:\Reforger Profiles\Experimental"