This is an excerpt from the Steam Forums:

• Edit your LaunchConfig.ini file (both client and server has one after being started once)
• Add the following line under [VMParams]: JvmParam2=-Dglass.accessible.force=false

NOTE: It is indexed so you have to add it after the other JvmParam options and with a higher number. Replace 2 with the appropriate next number.

WO Forum posts:

“Have a look at your keybindings.txt file for excessive duplications.”

“I used to have to sit and wait forever to get the launcher to open when I had a similar issue. It was a bug with keybindings.txt growing to a monstrous size by spamming duplicate lines, and going from like 3 kilobytes up to 20 megabytes or more.”