I think there is confusion here...

Previously..

Maschine was broken and Sonar was fine.

Now..

Sonar is broken and Maschine is fixed. It isn't just Maschine having issues with JP either.

So...

Run latest Maschine (2.4) with previous version of Sonar, or wait for next Sonar release.

I just got around to updating Maschine to 2.4 and Sonar (JP) doesn't detect the plugin.  The standalone version works fine, and my other DAWs detect the Maschine 2.4 plugin (all set to scan the Cakewalk VST folder).

cryophonik
I just got around to updating Maschine to 2.4 and Sonar (JP) doesn't detect the plugin.  The standalone version works fine, and my other DAWs detect the Maschine 2.4 plugin (all set to scan the Cakewalk VST folder).

I have no problems so it's some issue at your end. In preferences make sure your vst paths aren't overlapping and within one of them make sure the maschine 2.4 64 bit dll is contained within. Remove any 32 bit version.

Attempt a VST reset and also scan failed plugins.

You might need to reinstall machine from the 2.4 package (check the NI download folder). Make sure you check the vst paths during install. Make sure the 32 bit vst path is out of Sonar's file vst path (assuming you want 64 bit version). You won't be needing that.
You aren't using waves by any chance?
Ta

Doktor Avalanche
I have no problems so it's some issue at your end. In preferences make sure your vst paths aren't overlapping and within one of them make sure the maschine 2.4 64 bit dll is contained within. Remove any 32 bit version.

Attempt a VST reset and also scan failed plugins.

You might need to reinstall machine from the 2.4 package (check the NI download folder). Make sure you check the vst paths during install. Make sure the 32 bit vst path is out of Sonar's file vst path (assuming you want 64 bit version). You won't be needing that.
You aren't using waves by any chance?
Ta

I've already tried all of those and I don't install any 32-bit plugins, so that's not the problem.  I have a lot of Waves plugins, but they've never given me any problems and I've used them alongside Maschine 1/2 for years.  Why do you ask?

Doktor Avalanche
I have no problems so it's some issue at your end. In preferences make sure your vst paths aren't overlapping and within one of them make sure the maschine 2.4 64 bit dll is contained within. Remove any 32 bit version.

Attempt a VST reset and also scan failed plugins.

You might need to reinstall machine from the 2.4 package (check the NI download folder). Make sure you check the vst paths during install. Make sure the 32 bit vst path is out of Sonar's file vst path (assuming you want 64 bit version). You won't be needing that.
You aren't using waves by any chance?
Ta

cryophonik
I've already tried all of those and I don't install any 32-bit plugins, so that's not the problem.  I have a lot of Waves plugins, but they've never given me any problems and I've used them alongside Maschine 1/2 for years.  Why do you ask?

You say you don't install any 32 bit plugins, but if you are installing Maschine you will be installing the 32 bit plugin, there is no option not to (hence you need to throw it out of Sonar's path). You would have seen that if you had reinstalled Maschine recently as well.
 
There have been a lot of issues with JP and Waves plugins, I'm tempted to think this is related. Clear the Waves cache and check the forums for waves related issues and JP, plenty of threads to google. Are you sure you didn't scan for failed plugins?

Doktor Avalanche
There have been a lot of issues with JP and Waves plugins.

I use JP and the Diamond collection of Waves plug-ins. No issues.

Doktor Avalanche
There have been a lot of issues with JP and Waves plugins.

 

Anderton
I use JP and the Diamond collection of Waves plug-ins. No issues.

Yup but as soon as JP came out we had a tidal wave of complaint threads/posts about Waves plugins. Actually pretty much all of the issues (if not all of them) were not Sonar's fault at all, what appeared to be happening in that Sonar's new VST scanning mechanism exposed issues with old plugins laying around or some stuff laying around in waves cache, or plugins not being up to date... which Sonar had ignored up until now for some reason... One by one they all managed to resolve their issues (well mostly anyway).
 

To clarify, obviously many installers for many plugins do not give you the option to skip 32-bit installations.  I am meticulous about installing them to a dedicated folder under my x86 path, when possible (e.g., NI installations).  I typically delete those dll's after installation anyway, and Sonar does not ever scan them, nor does Sonar even know that the folder exists because it's not one of the VST scan paths.  I just double-checked to ensure that it is gone (after my third reinstallation) and indeed it was.  So, the 32-bit plugin is not the issue here.
 
 

Anderton

Doktor Avalanche
There have been a lot of issues with JP and Waves plugins.

I use JP and the Diamond collection of Waves plug-ins. No issues.

No issues here with JP and Renn Maxx, Gold, SSL, OneKnob, etc. bundles.  

Update: problem solved.  After re-scanning my plugins for the zillionth time, the scanner crashed, then crashed again, both on the same plugins (Fracture and Hysteresis by Glitchmachines).  So, I uninstalled those two, rescanned, and Sonar is now recognizing and loading Maschine 2 just fine.  

So I assume you got round to rescanning the failed plugins because that's the issue. Ta.