Ever since I upgraded to 3.1.3, the playback is very erratic

I am not sure if it is the 3.1.3 upgrade, of late, my play back has become very erratic. Thethe voice disappears for a few milliseconds and continues from the left out portion. It’s getting more and more frequent.

Now I get this error message half way through my recording ___" Recorded audio was lost at the labeled locations. Possible causes: Other applications are competing with Audacity for processor time. You are saving directly tp a slow external storage device."

I do not have any program running simultaneously

I don’t know how to change the device where the music is stored

Please help
Thanks
Dr Idiculla