Usually my Mac performs pretty comfortably but for the last hour or so it's been almost unusable. When I type it takes a few seconds to actually display what I've typed or just beachballs for a little while. If I try to open a new tab in Safari it takes about half a minute to actually appear.
When I opened Activity Monitor to see if I could work out what was happening "softwareupdated" was taking 100% CPU and Memory Pressure is in the red. I tried opening the App Store application to see if that would tell me but the application just opens but won't draw any content.
I didn't tell my Mac to update anything, and the App Store app seems useless right now, so how do I find out what is it doing that is causing this?