Carlospipo
A while back there was a thread which ended up in the same situation that you appear to be in.
Premiere elements crashing when adding disc menu on a mac
There does not seem to be a fixed answer in it. One suggestion seemed to be opening a new project which had no problems with the menus and that would trigger the problem project to work. From what you have written, it sounded like you have been there and done that.
I think this is going to go to permissions and preferences. But, not being a Mac user, I do not have any first hand information on that.
A common ground approach would be the deletion of the Adobe Premiere Elements Prefs file. But, haven't you done that already? Worth doing it
again after all the recent troubleshooting?
How many Timeline markers are you using? Have you allowed for at least a few frames between each marker....and no stop marker at the end of
the last item on the Timeline?
Please check out the above and then please let us know what is happening.
Thank you.
ATR