Targus ACP70EUZ

[uhdamm]

In the last week, my Ideapad Yoga 2 Pro had problems recognizing my Targus USB dock. Running Windows 8.1 with latest updates.
When turned on, I get a "USB not recognized".
I installed the latest firmware (v4401) from Targus, and tried upgrading to both 7.6 and 7.7 beta (uninstalls in between), but to no avail.

On one occasion, my Ideapad managed to start up and all USB devices attached and working.
On another occasion the startup failed as usual, but suddenly after 4 hours, the Targus was recognized and ethernet/external display was working for the rest of the day.

Any ideas how to solve this, would be appreciated.