I have also some problem with start FB 4.6. Since half of the week FB dont initlializing. I buy Master Collection and also I'm disg*&^% this situation. I must have it working immediately.
I thing it can be connected with Acrobat error because I was reinstaling Acrobat with the same problem. Now Acrobat works but FB still not answer. I reloaded FB and nothing.
I'm experiencing this problem on a regular basis. You could try deleting the .snap file in the workspace directory under .metadata\.plugins\org.eclipse.core.resources
That usually fixes it for me.
in this location a havn't got any .snap file but only those folders:
Ok, then it seems to be another problem. To ensure that the workspace isn't the problem you could try to rename the workspace folder and see if FB starts. If it starts there is maybe a broken project.
Just to be clear, there is a work around for this issue, however, when you have 20+ machines it is NOT very convenient. I don't remember where I found it, but I can explain the process. You can open another Adobe program in the same suite (Illustrator or Photoshop maybe), and then choose "Deactivate" under the "Help" menu. You will be prompted to log in to your Adobe account. Once logged in, you may go ahead and quit the program you opened. Then try Adobe Flash Builder again. It will open with the box asking you to "Sign In." Just click on "Sign IN" (even though you are still signed in) and it will take you to a message asking if you want to "Try" or "Activate." Just click on "Activate" and put in your license code and it will activate it for another 30 days. Hope this helps.