screen recording audio issues

[alpinestars69]

anyone know why a screen recording of a perfectly working video will be without audio. for example i could take a video that is 5 min long, and make 2 separate 1 min screen recordings. of the 2 recordings 1 will be exactly what i wanted & the other will be without any audio. or it will have audio for the 1st 40 sec. then no audio or the video freezes at some point & the audio is still there but the video is froze. anybody else see these things happen & can say how to fix the problem?

Version 2.2.1 Terry Pratchett (Weatherwax) (Intel 64bit)