First of all thank you for absence of option to write to support for technical question. It is always pleasure for me to pay a subscription fee and realize there is no option to contact support. You made my move to C1 easier.
Back to the problem.
LR 2015.12. Right after update.
When I open LR after restart it tries to open new instances of the same catalog again. Again and again. And just can't stop.
It continues after reinstall.
In addition to that it says that my trial has expired and proposes to buy the software again. Last time activated - 19 juillet 2017
Thank you for writing to us.
Its an activation issue in Mac machines.
If you have an active subscription & still you are getting trial error on your creative cloud & facing this multiple instance launch issue then,
please follow these steps:-
Sign out from creative cloud
Quit the application
Close all Adobe apps from activity monitor like:-
Adobe desktop services, CC library, core sync, creative cloud.
Now download Adobe application manager from this link & install
Now launch Lightroom & license it if ask.
Then close lightroom.
Open Creative cloud app & sign in & open Lightroom from there
Your issue will be fixed.
Please try above mentioned steps & let us know if that fixes your issue.
For more support you can call us at 1800-585-6687, or you can write us at firstname.lastname@example.org