Thanks for the replies. I'm actually running Sonar Platinum (Jamaican Plain) update and yes...this problem would make you think it's due to lack of RAM but my PC has 32 GB of RAM so I'm pretty sure it isn't from that.
To further muddy the waters - I didn't really use Sonar between the Ipswich update and the Jamaican Plain update as I was out of town for a few weeks. Plus, I had also upgraded my PC to Windows 10 within a day or so of installing the Ipswich update. No problems whatsoever prior to this.
So it may be that I need to start by rolling back my updates to see if either Ipswich or Jamaican Plain are the culprit. If not, it may be a Windows 10 issue.
Anyone else have any suggestions I could try?