+1, I was just playing with the trial, and there is a 4.0.4.001 build available. Definitely keep up with checking on updates as the version is new. I had the trial installation hiccup, and that error took two patches to rectify, so I am 6 weeks behind the power curve here.

I can't get Melodyne to install properly or uninstall properly.  I tried loading it as a plugin on a track and had to go through the entire download and activation process.  Activation failed every time with a server error saying the client wouldn't accept the license.  I tried fixing the install, but the install program doesn't see anything wrong. So of course I tried uninstalling so I could start from scratch and Melodyne won't uninstall.  It stays in my "Programs and Features" list.  I tried deleting all the Melodyne directories, but there must be registry and other stuff I cannot find. So Melodyne is completely unusable right now.  Anyone have any tips for me so I can get this plug working?  Thanks.
 
UPDATE - I deleted all Windows 10 registry entries and all Melodyne directories and reinstalled. NOw the Cakewalk Plugin Manager says the plugin is not installed correctly. I wrote Celemony a help request email.  Sigh.

The email request to Celemony is the best route to go. It may take a couple or three days to hear back until you get on their "squeaky wheel" radar.
 
My personal issue was my activation went through, but my computer crashed so the demo (client) never went active. Although Celemony initially said they had no record of an activation, the email reminders of "demo time running out" made me reopen this. Until the 4.0.2.003 update the activation page (online) actually removed the demo entry for this situation; but suddenly it was view able again and gave a popup of "already activated."
 
The solution was they simply needed to reset my entry in their server. What made me most irate is that it is my understanding that an internet connection is required to use Melodyne 4 (sans ILok) anyway. I am always connected, only on one machine, yet their "phone home" feature doesn't check the client side's functionality - only that their server has your computer ID on file.
 
Perhaps my standards are based on the higher end gaming community... During a program start they patch/repair the client when necessary in addition to the "server handshake." I am not sure I have come across anything DAW-related yet that pops up "Hey, your installation is FUBAR, want us to fix it for you?" In my particular case it could have been as simple as "Oh, your computer shows the demo active... here let me activate that for you." Perhaps too simple of a concept... but I happen to like simple.

You can search for Celemony and or Melodyne and cream those keys too.

UPDATE - The 32-bit version is working; the 64-bit version fails. So what I did was to uninstall everything and reinstall ONLY the 32-bit plugin. So that's how I solved it.

I just want to add my 2 cents. Yesterday I edited around 7-10 small clips with melodyne, And then it started crashing Sonar every time I tried to open a clip in Melodyne. I also made the mistake of upgrading to version 4.  Can we go back to an earlier version? If yes how?  And I also wonder if people are complaining to Celemony? I certainly intend to put a bug report in. It's so frustrating! I'm so close to finishing up my CD!

i tried installing Melodyne 4.0.4 2 weeks ago on my backup rig & it caused massive errors & could not be scanned by the VST scanner.  i immediately contacted Celemony support & have still not heard back from them (with the exception of a tweet apologizing for the delay).

I asked about earlier versions and Celemony confirmed that the upgrade 1) requires relinquishing a previous version and 2) an internet connection (or iLok) is required. The only recourse you would have is to contact them directly.
 
I have not experienced the SONAR crash with the trial (yet) but not used it extensively either.
 
Although not elegant, an option for you is to try Melodyne in stand-alone mode.

mettelus
I asked about earlier versions and Celemony confirmed that the upgrade 1) requires relinquishing a previous version and 2) an internet connection (or iLok) is required. The only recourse you would have is to contact them directly.
 
I have not experienced the SONAR crash with the trial (yet) but not used it extensively either.
 
Although not elegant, an option for you is to try Melodyne in stand-alone mode.

I had forgotten or not known that there was a standalone version. THANKS! A pain in the a$$ but better than not finishing my CD in time.

I found that the 64 bit version failed to install, but the 32 bit version installed fine. So I uninstalled all of it and reinstalled only the 32 bit version. Works flawlessly.