I've used melodyne ARA to create a midi double of a snare that came to me over compressed. It seems to have done a good job figuring out which notes are snares and which aren't. I've also done the same with a bass DI with decent but imperfect results. The main issue is that a few notes will be detected but wont play back and also notes can't be moved or they become silent during playback. I don't do this sort of thing regularly so I'm in uncharted territory. I can see them in the notation and piano roll but they never trigger the sound.
 
I'm using Dimension pro and session drummer as my instruments. Generally I'm pleased with the results but since I can't edit it or fix these issues it's not really usable. 
 
Any suggestions?
 
Cheers

its hit or mis unless the signal is clean and free of defects.
I usually do this and then tune it up.
go in to piano roll and move notes, velocity's, exc.

I haven't had a chance to work with Melodyn yet but my understanding is it will create a midi event just like we did in the past with Audio snap, correct. The difference should be audio snap could only do one note but Melodyn should create multiple notes, am I still correct?
 
So once it has done this you'll have to work with them a bit. Change the velocity? 
Bass notes are sometimes a problem if they are below the range used by the synth. 
Try shifting them up an octave. 
Drums you'll have to assign notes that are triggering the correct sound. 
I don't understand that your saying you could't edit the notes? Are they not midi now? 

Silent notes may be due to extremely low velocity, but more likely it's just that your Prepare Using buffer for MIDI is too low. This is the most common cause of MIDI notes being dropped on playback. Try the old default of 500ms in Preferences > MIDI > Playback and Recording. The X-series default of 250 is too low in a lot of cases.

BrundleFly
Try the old default of 500ms in Preferences > MIDI > Playback and Recording.

 
I'm guessing this one.

Sometimes the end of a note is rightupagainst the beginning of the next note, and the note-on gets missed. When doing the Melodyne-to-MIDI thing, the first thing I do is change all note lengths to 98%. That solves it. If that's the source of your problem, this should fix it.
 
When I first started doing audio-to-MIDI I wasn't that impressed, but I'm learning my way around it and results are improving considerably.

Melodyne Essential can only work with monophonic notes. You need to upgrade to Editor for DNA (Direct note access) and polyphonic note access.

Here's a link showing the features of the different Melodyne versions..

http://www.celemony.com/en/melodyne/functions

Hey, sorry I disappeared on this one. Was involved in an accident over the weekend and ended up in the hospital for a few days including a surgery. I'm home now but haven't returned to work. I'll go in this weekend just to test the waters.
 
I'll look into some of the suggestions but I clarify some of the stuff too.
 
There are three tracks I'm working with - kick, snare, and bass are all generating piano roll info that looks good but some notes (and they're always the same) won't play. If I modify them to raise the velocity or duration it still doesn't play. I've also noticed that if I try to drag a note forward or backward in time it will not play once moved. If I end up having to rely on these sounds then I might have to print the synth tracks and hand align the stuff that needs tweaking. That will suck but I suppose it will suck less than other options. I guess that's life but it seems like this should work. Maybe it is a midi buffer. 
 
Cheers.

Yikes. Sorry to hear of your mishap; Glad you were able to check back in, here. Dollars to donuts it's the MIDI buffering with those symptoms. Good luck on all counts.

Oww, speedy recovery there wmb.
I'm wondering if the initial audio you received was just a bit mullered and occasionally over-squashed by the compression before it was exported?...and assuming there was no "non-destructive" audio given to you
I'd guess then that if a raising of the midi buffering still has no effect on the current source audio, that going in manually afterwards may be a time-consuming but necessary thing.(I'd cheat and copy/paste a few after a while, to be honest...!)