This is a known issue (bug)
that has existed in XSite Pro for years. It happens when Windows runs out or gets low on memory handles. That is, if it's a case of the Design toolbar loading and then disappearing. If the Design toolbar has never loaded, you might have a .Net framework issue. Best thing to do in this case is to contact the XSitePro Help Desk: http://intellimon.helpserve.com/
Sometimes, closing and restarting XSite Pro will get the Design toolbar back. If there are memory issues it will disappear again.
I have 4GB of RAM and have had this problem with XSite Pro 2.0-2.5x. It always happened when I had at least one Microsoft Office application open and had done a lot of copying an pasting from Word to Notepad++ to XSite Pro.
The Disappearing Design Toolbar is, in reality, an issue with the Pinedit Design (WYSIWYG) editor in XSite Pro and (apparently) not something Intellimon can fix.
Please Intellimon, get a better WYSIWYG, professional grade editor.
I solved the Disappearing Toolbar In Design problem with Cleanmem: http://www.pcwintech.com/cleanmem
If you can't get it working a as a Windows Process, just put a Cleanmem shortcut on you desktop and run it before you load XSite Pro.
Here are two previous threads discussing this issue and how to resolve it:http://www.xsitepro.com/messageboard/viewtopic.php?f=3&t=21375&p=87730&hilit=design+toolbar#p87730http://www.xsitepro.com/messageboard/viewtopic.php?f=3&t=21223&p=86993&hilit=design+toolbar#p86993