Did you try using a Save As and giving it a new name? You could also try outlining the fonts as there might be problems with those. AI is getting much more picky about fonts with each new version.
Yes, I tried using Save As and changing the name. I also tried saving in other formats (PDF, EPS) but it won't let me save in those formats either.
I'll try manipulating the fonts. But the strange thing is I have very similar files with the same fonts and they open just fine...
What happens if you select all, copy and paste into a new file? Can you save that?
Tried that too. Didn't work.
But I just tried deleting some text. And it worked!
Looks like the font in question was a cheap, free font I once used many years ago. Probably best for me to replace it anyway.
Thank you so much for your help
I would do this with all of your files using these free fonts fro years ago.
The way to find out which files have these fonts is to select them in the bridge and look at the data. The Bridge will show you what fonts where used in any illustrator file and it will show you a preview of the document as well so you will even know if you want the file.