I updated the laptop from 5.0b to 5.1 and the yellow triangle was displayed over the Sync arrows. The Logos log states:-
Error LDLS4.AppModel Sync errors preventing local migration of old preferences. Some preferences may be missing until sync is successful. Preferences changed in the meantime.
6646.LogosSyncPref.log
My beta 5.1 installation continues to sync normally.
What to do?