A couple of months ago, I started to experience random spontaneous system reboots while using Lightroom. After upgrading Windows, video drivers, and BIOS the system reboots started to occur within 30 seconds of opening Lightroom. Thinking it was a heat issue, I replaced the CPU cooler with a more powerful model which improved system cooling but didn't stop the reboots. After loading a number of Lightroom catalog backups to isolate the issue, I determine that it occurred when Sync started. I would expect that if sync is broken, it would result in errors, or crash Lightroom, but causing a full system reboot is very unusual. Once isolating the issue to sync, I deleted my entire sync catalog via the web interface. Now, Lightroom Classic runs and syncs with no issue. Something in that online sync data was causing LR to force a system reboot. This was very challenging and time-consuming to track down. While I'm glad to have solved the issue, I'm concerned about the reliability of Sync.