What are your PC resources? Speed, RAM, type of PC, OS?
Have not encountered this issue with the 126.96.36.199 build.
It sounds like your issue occurs in streaming mode and is worse with more channels. This increases RAM load and PC will fall down without sufficient RAM when samples are maxed in PicoScope.
Not sure why the earlier build worked OK unless the settings used were different.
(The Picotologist) http://www.autonerdz.com
THE PicoScope Automotive Authority
In North America