My HP Split X2 running Windows 8.1 will sometimes, not all of the time, act very very slowly during shut down and boot up. The spinning dots spin very slowly, and the lock screen and login screens are very laggy. Then, after about 15 minutes, everything goes back to normal performance.
And, this problem doesn't even happen all of the time. Yesterday, for almost the entire day, it acted this way. Then, at night, it was normal, and is normal as I type this. What's more is that when it happens, I watch the Task Manager, and CPU, Memory, and Disk are all normal. No spikes in usage. I have also confirmed that no automatic maintenance is running during this time (this was the case a few times in the past so I eliminated this as a root cause). I also ran full system diagnostics (Esc and then F2 during boot) and no problems were found.
Anyone else had this random, not always reproducible problem? How can I troubleshoot it if it doesn't happen all of the time?