Serious issue!!.. I've been using Logic as my main DAW for over 10 years now. I just decided to upgrade my Logic Pro 9.0.0 to 9.1.8. Though I have had absolutely NO tech issues up to now. After the upgrade I opened up one of my Sessions and started. I loaded the ES2 and started to go through my sound library. I would start to play and then the sound would disappear, I checked my MIDI Settings and nothing was amiss. I started to play around with setting and still nothing. Then I opened up a bunch of other Logic Software Instruments and the same thing. Some didn't even sound at all. Others would play for a bar or two and then cut out. The odd thing here is that none of my other Soft Synths like Absynth or Omnishere seemed to be effected. My Fxpansion Drums were fine, Toontrack Superior Drummer, u-He Syths, All of the rest of my Native Instruments all work like thet are supposed to. I've dumped my Library Prefs from my hardrive pref folder, reinstalled my Motu Audio Driver, still...nothing....What the Hell is going on here...I need some help. Has ANYONE had a similar situation and do you have a work around...I've got 2 albums due out and this is just driving me batty. I can't figure this out..Please help...I don't want to have to reinstall my Logic Pro 9.0 and go through the whole process of loading all the external plugins if I can help it. Please help

Restart computer? Does it happen with the default Logic Empty Project?