selected font failed during last operation

So Im getting this message 'selected font failed during last operation. If problem persists, please disable the font', when I open a file.
I recently noticed that my Open Sans Bold had vanished from my fonts in Photoshop so I installed the whole family from Google. This may have created a conflict. So I uninstalled all open sans and loaded again. Now  I get this message whenever I try to open a file that uses the font. 
I'm at a loss as to what to do. 
any ideas?