When Control Room is On , sound disappear sometimes

Hi Everybody!

My problem is:

when i activated control room , sometimes fader of input channel do not respond when i move it with mouse and no sound until i move master fader or until i make reset from device setup. Sometimes faders of input Chanel do not move at all or they move with stops “like magnetic cursor”.
This problem comes only when control room is “on”, when i use normal outputs, there is no problem.

I tried to change buffer size of my interface, direct monitoring , boost audio priority, multy prossesing, activate steinberg power scheme… no difference.

VST performance works at 10-15%

My PC has : Intel i7 3.07GHz , 12GB RAM. My interface is MOTU ULTRALITE MK3.

Thank you!