This should have nothing to do with ASIO settings, as the audio interface is not involved in rendering operations (unless it's an audible render). It's entirely possible, however, that it's some kind of buffer starvation - just not audio buffers.
 
The clue is that you can freeze individual tracks OK but have the problem when exporting the entire mix at once. Technically, both are exactly the same process - except for any master bus processing that would be included in a full export but not a track bounce.
 
PumpDataMSec would be my first stop. This TTSSEQ.INI setting corresponds to the "Prepare Using ____ Millisecond Buffers" (Preferences -> Playback and Recording). Some bus effects, e.g. linear-phase EQs and other plugins with large internal buffering, can cause dropouts with virtual instruments. In my case, on my old computer I had to set this parameter to 1000 when using Ozone's most-demanding modules.
 
Try, as an experiment, bypassing all effects before exporting and see if the dropouts still occur.
 
Stretching into less-likely territory, it could also be caused by an I/O bottleneck. Try a slow bounce. If the slow bounce succeeds but a normal fast bounce fails, it could be a case of drives not keeping up or insufficient RAM for Kontakt preload buffers. 

Just as a quick test, try unchecking the 64 bit double precision engine (in your screenshot).
FYI- No worry's about the slider being grayed out, that's normal (your Focusrite controls the size/length).
 

scook
May want to visit AUD.ini. The settings may be edited in Preference > Audio > Configuration File. To see "Configuration File" option make sure the Advanced radio button is selected at the bottom of the Preferences dialog.
 
There are three variables I might tweak to see what happens

• ExtraPluginBufs - maybe start with 32 (This is what I use but like all these setting there is no magic number that applies for every setup)
• AllowOfflineRenderMixThreads - normally enabled, try turning it off for this bounce only
• BounceBufSizeMsec - set to the max, 350 for this bounce only

Tweak them individually before trying combinations. The is not much information about these settings but what there is may be found here

Hello Scook,


Thanks for your input; I appreciate it.
 
Right .. here goes .. I tried the following individually as you suggested.
 
* ExtraPluginBufs: This was set at zero so I set it at 32. Result ~ I had a clean bounce, no crackles, fizzes, pops or stuttering.

* BounceBufSizeMsec: This was also set at zero so I tried 250. Result ~ I had a clean bounce, no crackles, fizzes, pops or stuttering.

* AllowOfflineRenderMixThreads: As both the above appear to work, I left this at default (Enabled).

 
Regarding the BounceBufSizeMsec, you mention setting "for this bounce only" so is not 'safe' to leave this at my setting?
 
At this point this seems to have resolved things but knowing my luck the fizzes will be back tomorrow.  I'll try a few more this afternoon just to confirm.
 
Thanks very much.
 
 

bitflipper
This should have nothing to do with ASIO settings, as the audio interface is not involved in rendering operations (unless it's an audible render). It's entirely possible, however, that it's some kind of buffer starvation - just not audio buffers.
 
The clue is that you can freeze individual tracks OK but have the problem when exporting the entire mix at once. Technically, both are exactly the same process - except for any master bus processing that would be included in a full export but not a track bounce.
 
PumpDataMSec would be my first stop. This TTSSEQ.INI setting corresponds to the "Prepare Using ____ Millisecond Buffers" (Preferences -> Playback and Recording). Some bus effects, e.g. linear-phase EQs and other plugins with large internal buffering, can cause dropouts with virtual instruments. In my case, on my old computer I had to set this parameter to 1000 when using Ozone's most-demanding modules.
 
Try, as an experiment, bypassing all effects before exporting and see if the dropouts still occur.
 
Stretching into less-likely territory, it could also be caused by an I/O bottleneck. Try a slow bounce. If the slow bounce succeeds but a normal fast bounce fails, it could be a case of drives not keeping up or insufficient RAM for Kontakt preload buffers. 

Hello biflipper,
 
Thanks for your help.
 
The ExtraPluginBufs and AllowOfflineRenderMixThreads suggested by Scook seem to have worked and bouncing to audio now has clean audio.

 
I shall also try your suggestions.
 
Incidentally, I have tried to reply to Skook but my posts disappear.

Have you tried a realtime bounce instead of a fast bounce?

chuckebaby
Just as a quick test, try unchecking the 64 bit double precision engine (in your screenshot).
FYI- No worry's about the slider being grayed out, that's normal (your Focusrite controls the size/length).
 

Thanks for the info chuckebaby. Skook's suggestions appear to work although it would be just my luck the interference returns tomorrow. I'll also try your suggestion as well.
 
PS I don't know know what's up with the posting, some of my posts are disappearing.

gustabo
Have you tried a realtime bounce instead of a fast bounce?

Hello Gustabo,
Thanks for your suggestion. Yes, I did try that with the same result.

The spam blocker deleted your posts. I put one of them back.
 

Michael.b
Regarding the BounceBufSizeMsec, you mention setting "for this bounce only" so is not 'safe' to leave this at my setting?

It is probably OK but I have no experience leaving it set at anything other than the default. I do have ExtraPluginBufs set to 32 and have read that others have found a non-default value setting useful.

scook
The spam blocker deleted your posts. I put one of them back.
 

Michael.b
Regarding the BounceBufSizeMsec, you mention setting "for this bounce only" so is not 'safe' to leave this at my setting?

It is probably OK but I have no experience leaving it set at anything other than the default. I do have ExtraPluginBufs set to 32 and have read that others have found a non-default value setting useful.

Thanks Skook, much appreciated.