Matthias, Your comment does not relate at all to this thread.
I cannot repro the issues you described, both bypassing or powered-off states are saved correctly and if changed after re-opening a project, everything works as expected.
So I wanted to load your npr to have a look at it, sorry for my attempt to help.
Oh sorry Matthias! I totally misunderstood your post, now i understand, my bad 
Yes I had three QUADS, thats why you can’t load the whole session.
This issue is well known on this forum and others and plenty have experienced it. It is also rumored that this issue has been reproduced with non-UAD plugins.
No problem. From what I can see it doesn’t happen on PC.
Btw., all UA plugins have a power-off button that keeps the PDC active, so no audio gaps are created. Isn’t it favourable to use this button instead of the Nuendo power button ?
Not if you want to conserve DSP.
It does, Matthias. It’s happened to me with the P-LIM for starters.
It’s very hard to do a 100% repro though, but it has definitely bitten me in the rear.
Me too…
Awkward, but truly annoying on larger projects…
It is really tough to repro for some unknown reasons, as you say, but yes,… it happens on PC, too.
Big K
it always happens to me on PC…nothing hard for ME to reproduce…
rsp
Strange. It really never happened to me … yet…
Nuendo 5.5
OSX 10.6.8
This just happened again to me in Nuendo 5.5 32 bit…
- copied two power off UAD insert from one track to several (10) others
- power on the copied plugins and bounced their tracks down individually (I assumed the inserts I copied would be processing)
- after bouncing I listened back and the insert I copied that had been powered on did not process any audio
- went back to the tracks and verified with playback the plugins were not processing
- toggled the mono / stereo mode (top right) and they began processing audio again
This time I didn’t even close the session. During my session, copying inserts that were powered off caused them to not process audio.
This issue is nasty, users should not have to be concerned that every time we mixdown any plugin in our mix may or may not be processing audio.
Please SB comment on this issue.
I would like a comment from them as well, because I am so careful that I actually open EVERY plugin gui to verify things are correct before finalizing. I could save some time if I didn’t have to check. I suppose I could just trust my ears… BUT…
Just wasted another half hour because if this bug. Now I’m redoing my work… UGH.
I too have been experiencing this problem since version 4. User of Nuendo since v1.
I have to do the same things as others have said:
- Re-load the project after powering on the plugin or plugins.
- Go through all UAD plugs to make sure they are really processing audio.
- Move the UAD plugin to another track and then back.
This never happens to me with other plugins.
Also do you ever get the CPU overload message from UAD when you re-load a project that was working fine until you re-loaded it.
Please fix this guys.
Do we have a status on this from Steinberg?
BUMP 
They have not once commented on this issue.
It was indeed in the bugbase, but the issue couldn’t be reproduced.
Since this thread, I have tried to reproduce the issue myself, on 4 different machines, without luck.
To be honest, long time ago, I have had this problem too, but never was able to reproduce it.
It just happened “sometimes”. Now it has been years since I’ve seen the problem.
So, it’s obvious that “something” is causing this problem, though we don’t know what is causing this.
If someone can put the finger on it, I’ll be happy to submit it.
Fredo
Hey Fredo,
I’ve been trying for years to get exact repro steps on this. It happens to me quite often. I can provide a screen video of the bug in action.
I know you guys are strict in that bugs require exact repro steps, but in this case it may be very difficult to provide that. However, the number of replies to this thread shows that this is an issue for many users.
Is the previous bug in your database still alive?
If not, will this thread not become a bug before repro is found?
If that’s the case its unfortunate. Clearly we have an issue here that many users experience, but it seems it might not get attention unless there are repro steps found. And understandably it can be difficult to present to devs without repro.
I’ll make a concerted effort to track this down.
Thanks for the reply. Lets us know SB shares our concerns.
I suspect that it is a conflict with a plugin or set of plugins, for example Waves.
WHen I look at my systems, and we are running 5 of them each day, we also bumped into this, but it simply went away after soem time. If I look at the “progress” of these machines, the only thing that has “moved” were the plugin sets. The OS wasn’t changed (we were on XP for nearly a decade), the ASIO cards didn’t change (RME all flavors), etc …
Obviously Nuendo and UAD were upgraded too, but since people are still experiencing this today, and others not at all, it is near to impossible that it is a specific and UAD or Nuendp-only problem.
Again, I don’t doubt for a second that it happens, so no need for a screenshot or movie. But that isn’t enough.
We need to find what the trigger is.
As far as the official bugreport, this can be reopened within seconds. But we need a repro.
Hope you understand.
Fredo
Ill see if I can reproduce this somehow also. If I recall it seems to happen with templates that I have set up with UAD plugins in a powered off state. It also happens if I import some tracks with the same condition, UAD plugins powered off.
Is there a system information file/log that I can post that will be of help to anyone trying to figure this out?
I have had Waves plugins all the time that this has been going on.
Jim
Also happens when copying (drag and drop) bypassed inserts.