Check the /Library/Fonts folder to make sure that the font with the filename "HelveticaNeue.dfont" is installed. If this font is missing, iCal may not open. Reinstall the font if it has been removed.
For Mac OS X 10.3 Panther, use Font Book to enable the font.
To reinstall the Helvetica Neue font in Mac OS X 10.2.8 or earlier:
- Log in as an Admin user. If you are not an Admin user, ask one who is to follow these steps.
- Drag the font back into the /Library/Fonts/ folder if it was removed, or reinstall Mac OS X 10.2 or later.
Tip: If the font is installed, but you are using a font management utility such as Font Reserve or Extensis Suitcase, check to make sure that the font "Helvetica Neue" has not been disabled.