I've had this issue in two versions of W10 now. I'll be working in Lightroom normally, when it will suddenly start using around 30% of my processor. If I close it and open it again, it continues to use 30% of my processor, and becomes unresponsive. I've contacted technical support, and they have recommended updating windows once, and then recommended rolling it back when I contacted them again.
It's not a sync issue, as it uses 0Mbps of my network connection when this is happening.
I'm running an Intel i5 Quad-Core at 3.10 GHz, 12Gb of RAM, and an SSD. All of my video drivers are up to date, I'm using the latest release of Windows 10 (Version 2004), and my Lightroom install is up to date.
I'm out of ideas, can anyone help?
UPDATE: It appears to happen when I'm adding info to images (Captions, Locations). The only solution I've found is to re-install lightroom, which is obviously unacceptable.