I have same problem. Stable and Dev Build.

(Win7 64, notebook MSI GE60, i7-3630QM, Nvidia GeForce GTX 660M, DDRIII 8Gb)

Yes, its working on Dev-build ! Thx ;)

note: Stable build is still broken :(

Which of you have notebook ? Maybe a connection?

Dabz : THX ;) Worked for me too.

It looks like you may be experiencing what happened before in the previous update. I think you will need to unsubscribe to all the arma 3 steam workshop items.

Also you would want to go into your userdata folder in steam: located at <driveletter>:/Program Files (x86)/Steam/Userdata/<steamidnumber>/ and in there delete two folders: UGC & ugcmsgcache.