I had the same problem ‘Connection to protection device lost’ on my iMac. On my Win10 PC the installation and the activation of the license to the 1-gen-USB dongle went well. I talk to the tech support and they told me that probably 1 gen dongles affected.
As a workaround for MAC - activated C9 Lic. via Win10 elicenser is precondition:
- I downloaded the separate elicenser SW for Mac on the steinberg download page.
- included in this SW is the elicenses uninstaller
- uninstall the C9 elicenses SW incl. logs etc.
- reboot the MAC (don’t know if it’s really necessary, but I have done it)
- install e.g. C8.5.20 Update again, this installs an older elicenser (but not too old)
- with this elicenser you can to the maintenance task on the 1-gen USB dongle correctly and you can also start C9
please be careful: do not install e.g. Wavelab 9.0.35 Update this will install the latest elicenser SW and you will have the problem again