Voice recording starts ok then becomes distorted

Hi,

I have just tried to record some voiceovers in Adobe Audition and I'm finding that the recording starts off ok and then becomes distorted. 

Audio Hardware device class is set to MME, recording on a Samsung Meteor mic. No problems with this setup before today.

I'm not sure if this helps but I'm using a Windows 10 laptop.

Any pointers would be gratefully received 🙂