Just like the title says, some if not most of my plug-ins are causing this problem. If they just sit on the channel strip, fine, but when I open them to tweak, these error massages pop up and audio becomes jerky almost to a halt. I have used many of these plug-ins for over a year, and this is a recent issue, and seems to be getting worse. Thinking this may be a re-install logic, or re-install OS kind of thing? I'm using a early 2015 15" MacBook Pro, 16g RAM, 500g SSD. Latest versions of both the OS and Logic. Any insight greatly appreciated!

I should mention another symptom...Logic is crashing way more than ever. That used to never happen, but now it does almost every time I close a project, or try to change the I/O buffer size.

"Error while trying to synchronize audio and MIDI" is a familiar Logic error message—unfortunately, though it seems to suggest a specific issue, most of the time it doesn't really point to anything in particular. I also have Logic 10.4.5 & Mojave 10.14.5, and a similarly spec'd 2015 iMac, so I guess the basic rig should be fine, in theory.. It certainly wouldn't hurt to reinstall Logic; before doing that you might want to try blowing out Logic's Preferences (save the old files in case there's no difference) and test for a while—corrupted Preferences can cause all sorts of issues.. Reinstalling the OS could be a bigger deal—if you did decide to go that way (Apple would probably suggest that), make sure you have a current bootable clone backup first. But before you pull the trigger on any major reinstalls (or in case that didn't solve the problem), here are a few other things to consider, as far as troubleshooting.. - In case it really is related to the audio engine, try running Logic with the built-in audio driver instead of your interface's third-party driver - If the problem occurs only when plug-in windows are open, it could be a graphics issue.. Does it happen in sessions that use only the built-in Logic plug-ins, or only when third-party plug-ins are involved? You might want to try removing all third-party plug-ins temporarily and test for a while; if the problem goes away, then it's most likely a third-party plug-in compatibility issue—add them back in one/a few at a time to see if a particular plugin/brand is responsible. If the issue persists with just the Logic plug-ins, then there might be an issue with the graphics engine, depending on the graphics card in that machine; there have been Logic issues with plug-in graphics over the years, but I can't recall the specifics.. - In 10.4.5 Logic changed the graphics handling in the mixer displays, citing performance issues with the mixer open; maybe try shutting the mixer panel/displays to see if that affects things in any way..? - A number of people have reported issues with 10.4.5 and 10.4.6—just as a test, you could try rolling back to 10.4.4 (you do save previous versions when updating, at least for a while?) ;-) - A standard troubleshooting test is to create a new (temporary) User, and try running Logic in that User space; if the problem goes away, then something in your User space is incompatible or corrupted Unfortunately, escalating performance problems and crashing that are not tied to any new software or upgrades could indicate general Logic/OS corruption. You might want to try resetting the PRAM (I know, everybody always suggests that and it rarely has any effect, but it couldn't hurt). Running analyze/repair on the drive(s) also probably wouldn't hurt, I guess (though in my experience disc repair rarely solved any problems detected—wiping the drive and restoring files was always a better solution to drive corruption issues). Good luck with your troubleshooting—I've had to go through that at times, and I feel your pain; hopefully you'll find a solution sooner rather than later..

Thank you so much for that Joe. There are a couple of your suggestions that I will be trying out right away. I did try the re-install of Logic, no change...downgraded to 10.4.4, actually seemed to get worse. I re-installed 10.4.6. It does do it mostly when a plug-in is open, including logic native, but it will also happen occasionally with nothing open. It even happens with all tracks frozen. I'll give the pram thing a try, but i know what you mean there. You mentioned trashing the Logic preferences. I can't seem to locate them. I have no problem doing this as I have seen it help with other apps, just can't find them in there! I will do some other tests, because this is starting to get out of hand and seriously slow down my work. I also have a friend at Apple...they replaced the logic board on this machine last year and apparently I have a one year warranty on "anything", so I'll let her run some of their higher-level diagnostics on it as well. Thanks so much again for your detailed response Joe! Larry

Dang...one thing I forgot to mention. When I bring the performance meter up in Logic, I have a high level 75-100% on the last of the 8 threads, even with nothing playing. This seems odd to me...

The high CPU in the last thread is normal when you have an Instrument track selected and have played at least one note—that puts it in "live mode", where the VI and all the plug-ins on that track and in the path of that signal (including buses!) have to be processed on a single core (the last core), which then has everything active in ready mode. If you're not currently recording on an Instrument, simply select a non-Instrument track (i.e. a regular audio track) for playback & mixing—CPU should decrease and be spread out among the cores. (Apple has a knowledgebase document about how to game this.. https://support.apple.com/en-us/HT201838 It's a couple years old, but still relevant) The Preferences are in your Home folder ~/Library/Preferences: com.apple.logic.pro.cs and com.apple.logic10.plist if you decide to try that step. Maybe your Apple friend's higher-level diagnostics tests will bear fruit—fingers crossed! :-)

I've managed to eliminate the worst of the problems...the sync error. I suspect plugin incompatibility...or it could have been the pram, should have tried them out one at a time but yesterday morning I went ahead zapping the pram then going in and cleaning out the plugin manager. Over the years I've accumulated quite a lot of freebies and demos I never use or bought, so I had a mass disabling, and one or the other cleared it out. I've been keeping the cpu meter visible, and it's quite a difference. So that's all good. Thanks for the ideas. Never did have to trash preferences, but I'll keep that up my sleeve just in case. I still get an occasional system overload, but I don't think out of the ordinary when I have a lot churning, and freezing tracks solves that. The unexpected quitting when closing a project I'm pretty sure has to do with a specific plugin, but I can live with that. It's a great plugin! Been running various projects all day without frustration...what a joy! Thanks Joe

Great! I'm glad you got it going and everything's up & running normally again (for the most part). ;-) I agree with you, I'd also suspect it was most likely a plug-in issue.. When I upgraded my system to Mojave it broke a lot of plug-ins—like you I had a lot of freebies and demos cluttering up my plug-in folder. Some failed verification and a few seemed to work at first with the new OS—they opened up and passed audio initially—but then turned out to be unstable or not fully functional; that could be what was happening to your system as well. Anyway it sounds like you're back in business!