The standalone version of the launcher crashes for me, but when launching from Steam, Warframe does open and I am able to log in.
The tracking number for the crash on the standalone version is: WAR-3965302.
This crash was after the 35.5.1 update. I have tried optimizing and verifying from the launcher settings.
Side note:
I started playing with the standalone version of Warframe, then added Warframe to my Steam library as well to check out Tennogen.
I linked the Steam folders to my standalone installation to save space instead of having two copies of Warframe. But whenever I open Warframe from Steam, it always seems to do some updating to the launcher even if I have the latest game files downloaded.
So it seems to be strictly a launcher issue in the standalone version.
Note 2:
Deleting the EE.cfg did not work for me when launching the standalone version of Warframe.