On 2004.11.13, at 06:49 AM, Steve Bellovin wrote:

> When I run the latest firefox, I get the following message:
>
> 	Extension System Warning: Failed to set up default extensions
> 	files probably because you do not have write privileges to
> 	this location. While you can run Firefox like this, it is
> 	recommended that you run it at least once with privileges
> 	that allow it to generate these initial files to improve
> 	start performance. Running from a disk image on MacOS X is
> 	not recommended.*** loading the extensions datasource
>
> ...

This is where Firefox is trying to write some defaults and stuff. Since 
some of the defaults are supposed to apply to the global environment, 
it needs root permission (or equivalent). Weird and not very friendly, 
and a little worrisome, but you have to run it once with root 
permissions, preferably as root.