If so, try this simple test.
So I’ve been struggling with Windows 10 for a bunch of reasons, but the big one at the minute is that my start menu just stops opening. Along with that, the notifications pop-out and Cortana.
The biggest giveaway for me that a rogue process is at fault is that in safe mode its fine, and usually the first 5 to 10 minutes.
I got so frustrated that I opened task manager and started killing processes a few at a time and trying the start menu, including all but the key Windows ones and nVidia (because the last thing I need are MORE TDR errors…). Through this, I identified that the culprit is the “Runtime Broker” process.
Killed it, and the start menu, Cortana, notifications work again.
For at least 10 more minutes anyway.
In a tweet to me, Microsoft support say that the task involves the permissions for Metro-style apps. There’s probably a further root cause app at fault. But at least I can mitigate for now!