The game is bricked for me too, although it gets stuck at the very end of mission loading, with arma3 stuck on 25% (I have 4 core cpu). Nothing does anything, except alt-f4.
Even SP showcases don't work.
Does anyone know where the downloaded workshop files are stored?
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Deleting all workshop downloaded files didn't help.
Disabling all mods seems to have completely fixed it. So now going to check all 50-whatever mods one by one...