Illustrator 9 bug changes colors from CMYK to RGB

The current color settings can become corrupted in Illustrator 9.0.2 when attempting to save the file as PDF using the Screen Optimized setting. (We have yet to confirm this behavior ourselves.) Shannon Calvert writes:

"Any CMYK Illustrator file saved after the preferences become corrupt will switch to RGB without warning. The next time you open the document, it will tell you that 'this RGB document does not have an embedded color profile,' and all your CMYK colors will be redefined in RGB. Obviously, this will wreak havoc on a complicated file with many colors, and you can't 'undo' because the problem only occurs when you save and reopen the document. Trash the Illustrator preferences to return the color settings files to normal. Using Acrobat Distiller will avoid the problem altogether."

Update: Stephen Reiss writes: "This is a well known problem that has been discussed on the Adobe site for ages. The problem only occurs when you save a screen optimized .pdf. An easy work around is to save another copy of the file with the default .pdf settings. This will keep Illustrator from using RGB as the default color space."

Update: Chris Cousins writes: "Illustrator 9 will convert every document subsequently saved to RGB, with no warning. This bug was tracked down on the Illustrator 9 forum a few months ago, just before the release of Illustrator 9.02, and has been confirmed by an Adobe support tech. I use a script to launch Illustrator which deletes the prefs and backs them up from a new copy before launching."