Frozen keyboard and trackpad after session start,.

When I turn on my macbook the keyboard and trackpad work perfectly, in fact, I can use the keyboard to introduce my password and start my session.

Once session starts, the pointer appears on the upper left corner and I can not use them. External devices (keyboard and mouse) are recognized.

I made: test in safe mode, reset the SMC, re installation of the SO and updates; always is the same problem.

Any suggestion?

Thanks