I also have another question regarding recording an audio track !

When i record a vocal, it will record ok, then i delete the vocal, cause i am not satisfied
with the take and re enable the recordig and record again
after several attempt, when activating record enable, maybe for the ( 5th time, this is just an example )
and hit R and record, the audio start to stutter, while recording.
 what causes this ?

When this happen i need to reload the project again, and then it's all fine to record again !!

Sometimes i have encountered a half lengt recording of what i do on a take
but this do not happen often, but it can sometime..

anyone else have encountered this problem !
any solution ?

Soundblend
after several attempt, when activating record enable, maybe for the ( 5th time, this is just an example )
and hit R and record, the audio start to stutter, while recording.
what causes this ?

 
That kind of issue is going to involve your interface, drivers and audio config settings in SONAR.