"My Blocks" don't show up where they should and can't be deleted. In a simple program I created a simple custom block using the My Blocks Builder tool. It works fine in that program and shows up in the palette. However, other programs, old or new, cannot see that block in the palette. An exhaustive search of the Windows XP file system cannot find even a user "My Blocks" folder. Same bug in Vista, and Windows 7. (I believe Mac OS X 10.6.8 also had this problem.)
Any ideas? I will report this to Mindstorms tech support after I learn more.