Illustrator CS can't open Illustrator 10 eps files!

Part of my work is to convert client's artwork to colour separations for outputting on film for screenprinting. At work I use Illustrator CS on the Mac. Given the choice, I prefer clients to supply eps files. So this client supplies eps files created in Illustrator 10 and I can't open them. (something like "unknown file format" shows up on screen). Many phone calls later, I suggest, as a last resort, he creates PDFs from Illustrator 10. He does this and hey presto! I can open the files.

Problem solved, but what I would like to know is, has any body had similar problems and is there a reason why Illustrator CS would not be able to open Illustrator 10 eps files?

The only thing I can think of off the top of my head is that the client simply appended the ".eps" extension to the file but thats not what type of file it was actually saved as. (especially if the file was coming FROM a PC) I Can replicate the error you recievied saving a file in RAW format with the .eps extension appended as well as a few other fomats if I come from the PC.

Thanks for the input. Your idea is certainly possible, considering the weird and wonderful file formats customers can sometimes come up with! (My boss - who is, shall we say, not exactly PC savvy - once suggested I type .doc at the end of an Illustrator filename so he could open it in Word on his laptop!)

Trouble is, the solution may probably never come to light, as we mostly never get to see these guys in the flesh, and we got the job done in the end anyway...

I too, am at the mercy of what they send me... I share your pain. ;)