After we recently added and replaced a few icons, we started getting a nasty-looking dialog box in IE8 on Windows XP:
This page uses fonts that need to be temporarily installed. This is usually safe. Do you want to allow these fonts to be downloaded?
[Yes] [No]
It can be avoided by changing some settings in IE8, but this is terrible user experience, and doesn't appear to happen in other sites with web fonts.
The font in question is a custom collection of free web icons, collected and configured using the fontastic.me web app, and using their output for the @font-face declarations, character codes and css classnames.
The font has been in production for 4 months or so and was loading fine on IE8/XP without any dialog. After the latest update to the font (add/replace a few icons), this dialog began popping up. It's only in IE8 and only on XP (Windows 7 is fine).
Another interesting data point is that on IE9 (not IE8!), there's an error in the console, for both before and after the font file change:
CSS3111: @font-face encountered unknown error. zLhfkPOm_5ykmdm-wXaiuw.eot
This looks like this problem, but in our case the font loads fine.
Also, previously, we had trouble installing the font file on our local operating systems (to allow Photoshop comp'ing) and had to run it through font squirrel's processor to get it working. Now, it installs in the OS fine.
So my theory is that perhaps before, the .EOT file IE8 was using had some problems with it that prevented IE from trying to download it, and recently fontastic fixed these issues, paving the way for IE8 to attempt to download it. The fact that there are known issues with a common .EOT file generator may be relevant, though I don't know what tools fontastic uses.
What could cause the dialog to appear all of a sudden?
