VS2015 Why could IntelliTrace (debugging) fall off?

Question

.NET

At some point, all debugging fell off, I just start it and everything falls. Can anyone come across?
I tried to restore the studio and put it on a new one, everything is the same.

Answer 1

It was fixed by turning on Use Managed Compatibility Mode
But I remember that for some reason I had to turn it off, do not explain in clear language what it is and why it is necessary.