THE PROBLEM
For past two hotfixes including latest one I've been unable to succesfully extract using the elevator. RAM usage freezes and I'm stuck in an eternal loading sequence only cured by Alt+F4.
THE DIAGNOSIS
I found that the issue doesn't occur only on extraction, but on loading into mission as well. What triggers it is using the elevator two times in one session such as going to Orb Vallis from Fortuna and trying to go back. Loading to Vallis from Orbiter, going to Fortuna via the elevator and then trying to load into Vallis from Fortuna also replicates the same issue.
I tried verifying and optimizing the cache from the patcher but no luck. Using all possible combinations of 32/64 bit, DX9/10 and enabling/disabling multi-threading I found out that enabling multi-threaded rendering solves the issue (also mentioned by @Thoogah in another thread), however I have to disable it due to introduction of horrible input lag when framerate dips below 30. Unfortunately I can't enable or run DX11 so no clue if the issue still persists with it enabled.
THE WORKAROUND
It's possible to load into Vallis from Orbiter, mind my own business and then go back without any issues since I can take bounties directly from Vallis. The issue arises when I have to take a Profit-Taker bounty because they are not available directly from Vallis, and to complete one I have to use the elevator twice, to go up and return back down, which I can't do. Workaround is to take the elevator up, complete the given bounty and then take a bounty from the agent in front of Fortuna elevator, complete it too and then move into the neverending loading screen where I can safely Alt+F4 without losing all my loot.
Similar topics:
https://forums.warframe.com/topic/1057216-stuck-in-fortuna-gate-after-profit-taker-bounty-mission/
https://forums.warframe.com/topic/1027601-unable-to-extract-from-orb-vallis-playing-solo/
https://forums.warframe.com/topic/1049525-stuck-on-elevator-back-to-fortuna/
https://forums.warframe.com/topic/1052777-cant-load-into-4tuna-after-a-missionfree-roam/
https://forums.warframe.com/topic/1052782-fix-this/
