The reason why this has only reared its head in the past 6 months is the mysterious part !
I suspect a Win8/ 10 update gone bad. I understand that some behavior is now baked into Win10, which was usually part of the C+ distribution that was to be installed separately… They baked it in at a temperature that was set too high, overcooked dll’s… 
Hi Vinnie. I’m having the same problems on Windows 7 pro 64bit with Cubase Pro 8.5.2 !
Cheers
Ben
Any news about this?
Just to wait for a real fix, here is a Temporary “solution” : Plugins will No Longer Load Solution ! - Cubase - Steinberg Forums
Seems like a lot of trouble but its driving me crazy - running mixes for a client who wants lots of revusions and every time open a song it seems like something else is missing and I’m never sure what as the insert is simply now blank! So recalls are not accurate.
I have JBridge but if I bridge all my plugins and reload an exisiting mix will say VST3 plugins reload as JBridged plugins automatically?
I’ve just bridge my VST2 plugins and just effect Plugins, and let the VST3 & instruments like this (no bridge) all session reload correctly !
i just found out that when removing slate vmr, i can therefor load lots of uad plugs without reaching the limit yet!!
can somebody reproduce that? maybe slate vmr is part of this dll-problem. i have to investigate this farther before i can give a definitive statement on this.
Interesting…
I don’t use UAD but use loads of vmr and not hitting any limit as far as I can tell.
Interesting find, if this works then can just go back to the single versions.
EDIT: just tried this and no go unfortunately. I was able to add more Echoboys (one of the affected ones for me) but when i tried to load another Soundtoys plugin, Phasemistress, I was unable to.
I did seem to be able to load more plugins than before overall (even with VMR), up to about 160 and with my UAD DSP fully filled. Not sure if anything changed though.
When I have the ‘no further plugins will load’ issue my Slate VMR will load and all of the plugins inside it fine. Also my Sonnox Supresser will load as many more as I want. Waves will not except the API2500
I decided just now to take the time on my system to start an empty project. I just inserted Cambridge EQ on 8 inserts across like 40 channels (like 320 instances). My card maxed out but they never refused to keep loading. I then copied more channels and started adding Waves H Reverbs, Lexicons, Slate Virtual Mix rack etc etc…
I’m now up to 55 tracks loaded with a plugin in all 8 slots… thats 440 plugins running without issue. I closed and reopened the project and all plugins loaded back in again. Whats going on? Surely if theres a system limit issue before my CPUs being maxed out I’d have hit it by now?
However the projects I’ve been working on that have been all badly affected might have a far far smaller number of plugins running… havent counted but it looks like 30-40 and their the ones that I’m having the problem with.
This is gonna be super hard to track down
hi mart
if you just copy tracks with the same plugins, you won’t reach the limit. you’d have to load different plugins. once a plugin has been loaded you can add as many instances of it as you like. welcome to the wired world of computers 
So one .dll load per plugin but other instances share the same library of functions in memory?
So do we have a rough count on how many different plugins then will load ?
Apparently Studio One already released an update which “extends the number of possible unique plugins”.
Solved… I think by the latest windows update… Happy camper…
Really? Which Windows update is that? ?!!
don’t know really (I’m on win 10) but project that have problems before reload fine now…
I don’t know if this has been mentioned in this thread because I haven’t read the whole thing, but I read a user that used J Bridge and then was able to load plugins past what his original Imitation was.
Fabio if your watching in - have you any information on this ?
I don’t know if this has been mentioned in this thread because I haven’t read the whole thing, but I read a user that used J Bridge and then was able to load plugins past what his original Imitation was.
it was me… 
I’m afraid not, I just updated to the newest version of Windows and still have this issue.
This issue is so unbelievably game-breaking. Not having a complete session recall is absolutely destroying my projects. I have deadlines to meet and I’m literally stuck here repeatedly restarting Cubase in the hopes that everything has recalled properly…
I can’t emphasize enough just how terrible of an issue this is. It really makes me want to use other software instead, which is a huge shame - but at least I know my projects won’t literally be eating themselves apart.