Colorsync Engine is still not working correct in Snow Leopard 10.6.4

Question

Colorsync Engine in 10.6.4 causes Print faults in Photoshop CS5.
A light cyan tone is being printed around pictures, where there should be plain paperwite.
I really would appreciate some help.
The problem shows when using custom paper profiles.
(The only situation, in which the problem does not show:
If sRGB is chosen as the printerprofile or if the paperprofile is chosen that belongs to the mediatype chosen in the Epson printersetting. Both are no options as they do not allow to print a colourmanaged print)
So it is obvious that there is still something wrong in the way the different profiles are matched....

Answer 1

I am no beginner - you can believe this.
No insult meant at all. Just no way of knowing how much you do know on the subject.
I have custom paper profiles written for all my papers for this one printer Epson 4800 from targets I printed with no colour management from the printer driver and no colour profile tagged.
No problem there. That is the correct way to print the color patches for profiling.
There is no reason within the paperprofile to make the sourrounding area of the picture to be printed white...
In a very technical sense, there is. All profiles are built to include the ability to choose any rendering intent. So the option for Absolute Colorimetric is in there. Which leads to...
And besides that: How could a profile make an area be printed with a cyan tone that is around the image that is printed. In relative colorimetric rendering. How can you explain this?
It was just a thought. It wasn't until after I mentioned the possibility of using Absolute Colorimetric that you noted you always use Relative Colorimetric.
And the profiles worked before - under 10.5.8.
And they should in Snow Leopard. I'm using all of the printer profiles I made in Leopard for both an Epson Stylus Pro 4000 and a Xerox 6280DN in Snow Leopard. Color is identical from the same applications and the same test images. Both CMYK and RGB. I was able to easily test this as I have both 10.5.x and 10.6.x installed on two drives of the same Mac. So it was just a matter of booting into one, printing the images, then the other to do the same and compare output.
You noted at Adobe's forum:
Around the document, the printable space is filled with a very light colour.
Then printed it 5 to 6 times on the same sheet so it would be easier to see the cyan tone being printed. How was this tone added? I ask because your screen shot shows pure white as the background color. Is it neutral? Such as an RGB value of 253, 253, 253? If everything is correct (settings, profile, etc.), it should build up as a slowly darkening gray, not cyan. But you already know that.
But even if you choose no colour management in the printer driver, there are profiles and media settings that belong to the media you choose in the printer driver.
Not quite sure what you mean there. If you choose no color management, then any profiles in the printer driver are disabled. As far as the media settings, the paper you choose tells the printer the weight of the media going through it, so it can adjust the height of the guide tray. Important for heavy stock (canvas in particular) so it doesn't rub while going through. But much more importantly, it tells the printer how much ink to use. Plain paper will cause the printer to use a different amount of ink than if you choose something like Premium Glossy, even though both may be set to use a print quality setting of 2880 dpi.
The point there is that it is equally important to choose the exact same paper settings in the print driver as were used when the targets were printed, even though color management is turned off.
Actually, the issue may be how old these profiles are. I never print straight to the Epson 4000 since a profile can't account for drift. I go through the full version of the ColorBurst RIP for everything. The reason why is so you can account for hardware drift by re-linearizing when you notice grays starting to go pink/green/blue, etc. All inkjet printers drift as they are used. Meaning, the size of the dots change as the heads and ink pumps wear out. It's slow, but it does shift the color slightly as time goes by. Linearizing brings the gray balance and gamut back to its original point without having to create an entirely new profile.
A straight profile can't account for this. As the printer's color shifts, the profile can't move with it and colors shifts on your output starts to become apparent.