This can sometimes happen when the Mac OS or Audiodesk is updated. To fix this problem follow these steps.

- In Mac OSX 10.2 "Jaguar":
1. Uninstall Audiodesk using the Installer CD.
2. From the Finder's "File" menu, choose FIND.
3. Next to "file name contains", enter the word AUTH.
4. Before clicking SEARCH, click the "Add Criteria..." button, and choose VISIBILITY. Set Visibility to ALL.
5. Finally, click SEARCH
6. In your list of found items locate, "AUTH-Audiodesk 2.0". Drag this file to the TRASH, and empty the TRASH.
7. Reinstall Audiodesk using the CD, including upgrades. When you launch Audiodesk, you should be prompted to authorize again.

- In Mac OSX 10.3 "Panther" or 10.4 "Tiger":
1. Uninstall Audiodesk using the Installer CD.
2. From the Finder's "File" menu, choose FIND.
3. Next to "file name contains", enter the word AUTH.
4. Before clicking SEARCH, click the "plus" (+) button to add a new line of search criteria. Using the pop-ups provided, make this second line to "Visibility" and "Invisible items."
5. Finally, click SEARCH
6. In your list of found items locate, "AUTH-Audiodesk 2.0". Drag this file to the TRASH, and empty the TRASH.
7. Reinstall Audiodesk using the CD, including upgrades. When you launch Audiodesk, you should be prompted to authorize again.