Opera drives me crazy!

I want to migrate the settings, extensions etc. from Opera on my old Macbook to my new one.

Since the synchronization doesn't synchronize any extensions, there seems to be only the way to copy the profile folder.

So I installed Opera on the new Macbook and copied the folder
~/Library/Application Support/com.operasoftware.Opera
from the old Macbook.

After starting Opera no settings, extensions etc. were used from the (old) profile as if it were not there.
I checked the profile path in "About Opera" and it is correct.

Why does Opera not accept the copied profile folder?