Hello,
I have a problem with converting PS to PDF. It only happened once. The PDF has 400 pages.
The letters of generated pdf are missing ( example attached).
I reprocessed it, but eveything was ok.
What is the reason for this? Can this be logged? How to prevent this?

Many reasons could lead to that behavior. If you can't reproduce it at will, it could be a simple "glitch@ in the system which can't be prevent.

If you can reproduce it at will, I suggest you open a technical support call at 1-866-348-5863 or through our website.