I had all work database connections details with pwd stored in SQL Developer 4.0.2 configured in my Win 7 laptop. Currently I need to use our virtual desktop which has lower configuration Win XP.
When I try to use SQL Dev 4x it crashed and I decided to use lower version on 3x which opens fine.
I suggest you fix the actual problem rather than run away from it to a lower version and deal with those problems.
We can't help you if all you say is 'it crashed'.
1. what crashed? Sql dev or the os?
2. how did it crash? while starting up or after it started and you tried to do something
3. what messages were displayed at startup?
4. what did the log window show?
Post detailed info about your actual problem and people can help you fix it.