FONTS! Problems when upgrading to CC

Since upgrading to CC I am unable to work without wanting to tear my hair out and cry.

I am having problems with fonts (surprise, surprise!). 

Im opening old files and there are problems with missing fonts - but they are system fonts, so in my Suitcase application they are activated.  They are working and viewing fine when I revert back to CS6, but super probs in CC.

Does anyone have a fix, I am getting so frustrated......?