if anything cc is installed, uninstall it, https://helpx.adobe.com/creative-cloud/help/uninstall-remove-app.html
if the cc desktop app is installed, uninstall it, https://helpx.adobe.com/creative-cloud/help/uninstall-creative-cloud-desktop-app.html
clean your computer of cc files per http://www.adobe.com/support/contact/cscleanertool.html
uninstall your acrobat dc
restart your computer (don't skip this)
reinstall your acrobat dc and activate with your serial number
Hi,
Thanks for your help
I finally uninstall the software, restart and re-install after, type the license and login.
This work now.
FYI : I notice, before applying these change, there are an Adobe resource file (blank icon) locate on Login Items (Users & Groups)(System Preferences). This file was not there few month ago when install softwares...., I'm not sure if there is a link, but I removed it also, just before applying the uninstall.
Regards
LEJEUNE Daniel
info@dljmac.be