That circle does not looks like it’s generated by OSMC, that looks like it’s coming from some kind of addon you are using, if you you’d be best asking the developer of that addon.
Well I assume even with the wheel turning you should be still be able to login in via SSH and restart. That would be more healthy than unplug power.
To get a better understanding of the problem you are experiencing we need more information from you. The best way to get this information is for you to upload logs that demonstrate your problem. You can learn more about how to submit a useful support request here.
Thanks for your understanding. We hope that we can help you get up and running again shortly.
Apparently it was the Multi Slideshow Screensaver:
14:20:46.257 T:2583688176 DEBUG: Multi Slideshow Screensaver: _get_folder_images started with path: ‘//sys/fs/cgroup/systemd/system.slice/systemd-udev-settle.service/’
14:20:46.261 T:2583688176 DEBUG: Multi Slideshow Screensaver: _get_folder_images ends
14:20:46.261 T:2583688176 DEBUG: Multi Slideshow Screensaver: _get_folder_images started with path: ‘//sys/fs/cgroup/systemd/system.slice/hdparm.service/’
14:20:46.263 T:2583688176 DEBUG: Multi Slideshow Screensaver: _get_folder_images ends
14:20:46.264 T:2583688176 DEBUG: Multi Slideshow Screensaver: _get_folder_images started with path: ‘//sys/fs/cgroup/systemd/system.slice/nfs-common.service/’
14:20:46.266 T:2583688176 DEBUG: Multi Slideshow Screensaver: _get_folder_images ends
14:20:46.266 T:2583688176 DEBUG: Multi Slideshow Screensaver: _get_folder_images started with path: ‘//sys/fs/cgroup/systemd/system.slice/x2dpvscan.slice/’