urgent help needed serious midi problems

Hi Folks,
I havent posted here for a while (was avoiding the X1 debacle and mainly use an ipad for the net which this forum doesnt support ), I bought and installed Melodyne DNA which has completely scuppered my system  (I have had to get a new license for notion 3, some Kontakt libraries have went wonky and it has broken Sonar),
I am still using sonar 8.5.3 (most of the action seems to be in this forum so i will post in both ), I bought and installed X1 and absolutely hated it so that was uninstalled.
basically melodyne made sonar crash with alarming frequency and now ( i reinstalled it ) it still crashes a lot more (during export for example ).
my main issue is that midi parts previously recorded are not being sent properly to virtual instruments.
ie I have a harp part that plays fine triggering an external synth but when sent to the garritan library in Kontakt player then kntakt is not receiving all of the notes. the notes used icon confirms this. I froze the track and this seems to work but that doesnt give me midi edit capabilities.
in session drummer a hi hat click on every beat part in 4/4 will not consistently play.....the midi part meter says it is sending out all the info but somewhere along the line it is being diverted (I think)
the same hapenns in BFD 2 , beatscape , emulator X2 and true pianos.
after reinstalling 8.5.3 i rebuild the initialisation file and that didnt seem to help

does anyone have any solutions?

Thanks in advance
Andy

The PumpDataMsec aud.ini value, which corresponds to the "prepare using N millisecond buffers", may need to be raised in order to avoid dropped MIDI notes or soft synths not playing at all. Using high-latency plugins such as PerfectSpace exacerbates the symptoms.

The default is 500ms, but if MIDI playback is unreliable CW recommends a setting of 700 or higher. Setting it too high will only cause latency problems if you're controlling outboard equipment via MIDI, but shouldn't be a concern if you're completely ITB.

I have never encountered this particular problem myself, and that's probably attributable to my practice of freezing soft synths individually prior to final mix/mastering. By the time I'm adding high-latency plugins to busses, MIDI buffering is no longer part of the equation because my projects have no active MIDI in them anymore.