I am setting up a school with LTSP, and have encountered a strange problem.

There are 30 or so computers up and running as expected with Edubuntu 12.04 and LTSP, and defaulting to Gnome. But there are 3 computers that act strange. 2 of the computers are identical, the 3rd is a different brand, etc.

These 3 computers boot successfully (PXE) and you can log in as expected. The background image appears almost instantly. But then it takes MINUTES to get the menus and the desktop icons - this is the strange part. But then after the menus and icons appear, programs open quickly and everything is as expected.

Does anyone have any ideas why these 3 computers are acting differently?

The menu/icon problem makes it difficult to use in our school environment where students log in and out regularly during the day.

Thanks in advance for any suggestions.