Error while trying to synchronize Audio and MIDI.

Hi all, I have a problem with Sample Rate on an i7 iMac running Logic Pro 11 with a Motu 10Pre. Everything (Audio Midi Setup, Logic Pro, Cue MIx and the MOTU with internal clock assigned) is set to 96K for great headroom, it was all working beautifully but now I get this Alert:

Error while trying to synchronize Audio and MIDI.

Sample Rate 93,819 recognized.

Check conflict between Logic Pro and external device.

It driving me nuts that I'm doing something probably very basic and very wrong. I've been recording for years with no worries, but updated OS and equipment has got me beat. Can someone please help??