Hello,

I have had an issue for the longest time.  Meaning years (!).  I'm gonna try to do my best to describe it.

My system: Mac Pro 5.1, 2x 3.46GHz 6-Core, 64GB RAM, OS X 10.12.6
FYI, the issue has been present on each OS installed/upgraded on the Mac throughout the past few years.

So... first of all, I HAVE TO leave the UFX switched off before turning on the Mac, otherwise, the issue gets even more stubborn.
Once Mac is fully booted, I switch on the UFX.  If I am lucky, TotalMix (TM) pops up in seconds, and I am good to go.  But I am rarely that lucky.  Usually (maybe 19 time out of 20), what I see instead is that the dot (indicating an active app in the dock) under TM icon is blinking.  Eventually, after up to 1 or 2 minutes, it will stop blinking, and one of the following 3 events occurs:

-1- TM window pops up, and I'm good to go;
-2- I click on TM icon, TM window pops up, and I'm good to go;
-3- I click on TM icon, nothing happens... (If I launch my DAW -Pro Tools, Ableton- at this point, it gets stuck at the "Initializing MIDI Drivers" stage, and need a force quit.)  So I need to force quit TM app, switch off the unit, then reboot the computer and start over.

I may need to repeat "-3-" a few times in a raw before TM ends up popping up.  But every now and then, this will be so persistent that I end up going through the whole, full uninstall and reinstall process.  And even then, I may need to perform a few '-3-" cycles before being good to go.

Yes... crazy... frustrating.  I do not dare shutting down my system once it's working fine, sometimes for days, to avoid having to go through this, and wasting a lot of time.

I am aware that this is an issue encountered by others, and over the years, I have tried every possible fix posted on this forum mainly.  At times, I thought the battle had been won, but then the issue always comes back, within a few days at best.
I tried removing MIDI drivers... tried switching between USB and FW ports after uninstalling and reinstalling everything RME... tried different Terminal commands like " kextstat -kl | awk ' !/apple/ { print $6 $7 } ' ", leading me to, e.g., remove antivirus app from my machine... Always with the same ending.

I even had the unit serviced a year and a half ago after experiencing noise bursts on analog inputs 1 to 8, pops when raising preamp gain from 0 up, and FX section not working.  The digital board was changed.  That did not resolve my TM issue.  (And btw, the noise bursts have been back after a few months, sporadically.)

Has anyone experiencing this issue been able to tackle it for good?

Thanks for your time ;-)