How do I update symbols in the Block Editor in the Quartus II software version 10.0?

In the Quartus® II software versions 10.0 and later, you cannot update the symbols for megafunctions or custom HDL files in the Block Editor if your project directory has spaces in the file path. For example, you are unable to update symbols if your project folder is:
C:\Documents and Settings\user_name\Desktop\project_directory

To work around this problem, ensure that your project directory file path has no spaces in order to modify your design files and successfully update your symbols in the Quartus II software 10.0 Block Editor.