btw, using the latest version (enhanced) on xp pro.

Latest version of what? What all do you have running on your desktop?

On XP, sdmcp.exe handles SysTray functionality

But only if you're not using the Win taskbar...

It's hard to be sure but it looks to me like the OP was talking about the Win taskbar.

If the problem was with a specific skin, I would say the system tray content margins are too big, which prevents the icons from appearing. You could try unlocking/relocking your taskbar, or maybe try stretching it to two lines tall, then put it back to the way you like it. If you don't have "hide inactive icons" enabled in the taskbar properties, you could try enabling that. Sometimes pushing the arrow button to slide the tray out and back in can get the icons to reappear. I've only encountered things like this when I'm creating a skin and expirimenting with stuff. I've never encountered it as a general user unless there was a problem with the specific skin I was using.

I've had the same problem for a while. The only fix I've found that works is to logoff and log back in after your computer boots up. It's getting really annoying though

I believe sdmcp, if the option is checked in SDC, handles SysTray in the native taskbar as well as taskbar replacements. Is that incorrect?

I don't actually know for sure... I always assumed you needed SDMCP to diplay the tray icons when you hid the Windows native taskbar (that's what I meant by "Win Taskbar").

I definitely notice subtle differences in the way the tray icons are displayed between 'native' and SDMCP which makes me think SDMCP is not used in the 'native' mode.

In particular I get 'phantom' duplicates of (particularly) network interface icons, and the 'offline files' icon behaves strangely under SDMCP but not natively.