mettelus
1) I am pretty sure the "buffer" is I/O buffer  (Advanced Mode: Preferences->Audio->Synch and Caching (the disc read/writes to smooth ARA performance)) and not Audio buffer. I remember early on I jacked my ASIO buffer through the roof and still got that warning... but if you set I/O buffers to 1024 that warning goes away (just verified this actually).

Yup, I've tried both and nothing keeps that dialog from popping up. Strangely, once it's been dismissed in a session, you can add another instance of Melodyne to another track and it doesn't pop up again.
 
But you're right; ignoring it seems to be the way to go. As I mentioned earlier, I've been doing that all along and getting away with it.

All this time I've been ignoring it and things seemed to work, but wondered what was going on. Thanks for lifting the veils of ignorance from my eyes

It seemed like a wonderful opportunity to use the much-touted new "toast notifications" but alas...

Sanderxpander
It seemed like a wonderful opportunity to use the much-touted new "toast notifications" but alas...

It's a message from Melodyne not SONAR.

It may not be the ASIO buffer that is causing the message and that's good to know; but Celemony does recommend setting the ASIO buffer to 1024 and I have had crashes and other issues when I did not.

konradh
It may not be the ASIO buffer that is causing the message and that's good to know; but Celemony does recommend setting the ASIO buffer to 1024 and I have had crashes and other issues when I did not.

Just curious... how much RAM do you have?

I have 12GBs RAM.  See below for more details.

I spent about 6 hours yesterday editing guitar parts and vocal part on melodyne. Compressors everywhere (sadly), 3 instances of Kontakt, addictive drums, various reverbs etc. No issues whatsoever and my ASIO buffer is on 128, so is I/O (8 times smaller than they recommend).
 
It really depends on your hardware and the way you have set up your system, so please don't take my advice, but from my angle I took their advice with a pinch of salt.
 
I can understand why they do this though, it probably cuts down the support calls. Every case is going to be different though...

konradh
I have 12GBs RAM.  See below for more details.

Of course (smacks forehead).
So, it likely isn't the amount of RAM, but here are a couple of other possibilities:
- hardware (as Alex said) Your motherboard's front-side bus, specifically. Which motherboard are you using? Or, is it a brand name computer and, if so, which brand/model?
- The 'fix' they recently did was geared toward getting Melodyne to work better with X3c or X3d and may not have fixed the problem in earlier versions of Sonar.
 

The warning message came up again, and I was thinking that Celemony, who in my view has an application as beautiful as when the iPhone first came out, with a simply amazing engine, that has unique features like snake tails in it's UI, came up with something as ugly as this.
 
I would have expected that Celomony would have done a full diagnostic of the PC and worked out how double it's performance automagically without the user even knowing what was going on, and then given a nice 3D visual similar to the film "avatar" to make it look as though the PC was running at optimum, and it would be correcting my posts as we speak.