Thanks everyone for chiming in.
So far I've been trying to stay at MC 8.4.5 on Yosemite/Sierra.
Somethings messed up cause Dongle Mangler states that my dongle expired back in Nov.
Which can't be since it works in the studio but nowhere else.
Plus it was upgraded prior to expiry date.
I guess it's time to waste my day with support.
Give Avid support (licensing) a call, and make sure your email on your avid account, matches the dongle SID account and Application manager is aware of those items working together.
I think when 8.0 or 8.2 came out i started having licensing issues with Avid not letting my dongle work with the latest version. Support would have to send me a manual dongle update file for 8.2 and 8.3 and 8.4..it was very annoying. Finally in 8.5 it all worked...not sure what changed, but everything is now on the same page.
And obviously if you are moving from box to box, you do have the same (or earlier) version of Avid on each box?