When I start the game it stops at 50% for about 3 minutes. I got a profiler output here (seems related to a close() method on a SFSInputStream object):
https://imgur.com/HFHzQDk
I tried logging but there is no information other than the visible delay between two messages (10:26 and 10:29):
https://pastebin.com/fhZS2g0U
Is this a known problem? My OS is Windows 10 x64 1803, and IL-2 Sturmovik from Steam with latest update (4.13.4).