[Desolis]

Hi, I have worked in my Mac for the last few years (currently OS Sierra V 10.12.6) with Pro Tools 10.3.5 and as it was working correctly, I did not installed the latest versions. A few months ago, PT began to give some minor errors until about a month ago when my Mbox 2 Mini stopped recording: The program identified it well as a Playback Engine but did not pick up the input signal.
Thinking that perhaps updating to a later version the problem would be corrected, I installed the version 11 but if I select the Mbox as Playback Engine when activating Play (both in playback and recording mode) the Stop is activated automatically and in the lower part "Pause" appears, however, if I select Pro Tools Aggregate as the Playback Engine, it works correctly. I´ve tried the follow solutions without success: I have installed version 12, I’ve reinstalled the Mbox driver, I have increased the size of the buffer successively to 1024, I have disabled the plug-ins, but the problem persists.
Notice that I am not very expert in rare terms.
Thanks in advance to those who can help me and my excuses for my basic English. I´m from Spain!
Desolis