for mission Overlord Surth-Velsok, -download "FAF_Coop_Operation_Overlord_Surth_Velsok" from https://github.com/FAForever/faf-coop-maps -extract this folder to C:\ProgramData\FAForever\user\My Games\Gas Powered Games\Supreme Commander Forged Alliance\maps -make 2 folders with same data FAF_Coop_Operation_Overlord_Surth_Velsok.v0000 FAF_Coop_Operation_Overlord_Surth_Velsok -enjoy

The blueprint loading process crashed. This is likely related to a (sim) mod

@asreall Because it only takes one of you to freeze the game