Some third party extensions which modify the standard Open and Save dialog boxes are incompatible with DiskTop. Known examples are Norton Directory Assistance from Symantec's Norton Utilities and SuperBoomerang from Now Software. Some of these extensions include options that can be used to turn off the extension when DiskTop is active. Check the documentation that came with the extension. Updating to SuperBoomerang version 4.0.2 or Norton Directory Assistance version 2.0.6 seems to correct this problem.
Some applications withhold large amounts of temporary memory.
These versions of these programs do not allow the DiskTop desk accessory to open. They do not prevent DT Launch from operating. Installing or updating to version 2.0.1 or later of Big Thesaurus or version 4.0.1 or later of Coach Professional fixes this problem. Users sometimes rename DiskTop to begin with a space, causing it to be listed at the top of the Apple menu. Make sure there are no spaces before or after the name.