What fonts are you using in those projects?
Have you installed a lot of fonts on your system?
The main font in that project is "Source Sans Pro".
I had a lot of fonts on that system. I deleted them all and started from scratch. It worked for some time. But I got the problem back again. I was not able to reconstruct when in started and why.
The only thing I know is, it always works fine with the software version in which the project was build.
So my question is, what can change in a software, that fonts work fine and become corrupt, after an update?! I still can use all the fonts in new projects, made with the updated software version and never get problems.
What is the best workflow to integrate fonts to our system for the future?
I haven't heard of an issue like this before. I'd recommend contacting Adobe support.
What is the best an most effectiv way of doing it? Never did it before.
Adobe.com/Support and there's a contact us button on the bottom somewhere. (Their webpages are different for different regions, so I don't know exactly what it'll look like for you.)
It was still a font issue! The font "Source Sans Pro" I used in that project had some installation issues. It wasn't uninstalled at all. Now I got it and reinstalled the font. The ATM Error is gone. But it was hard to find out why and which font it is related to. It would be great to have a guidline how to install fonts correct and where to get them from (next to Typekit), to avoid that kind of trouble.