The Opera 12 webfont bug

Opera has a bug related to its handling of webfonts (fonts that are embedded in Web pages that you don't have to install yourself): if too many webfonts have been cached (about 25 in my experience), Opera will sometimes show the wrong webfonts on a page that uses them. This would normally not be a problem if many pages didn't use webfonts for special symbols and icons; and if Opera wrongly chooses such a font, the entire page becomes unreadable. This bug occurs on all operating systems.

Solution

1. (Optional) Quit Opera. If you started it from a command line, you may randomly get [harmless?] error messages after finishing this procedure.
2. Delete all files in the folder profile\cache\assoc002\sesn, where profile is your profile folder.
3. If you have quit Opera, start it again.
4. Repeat this when you encounter the bug again.

Note: clearing the cache by checking "Delete entire cache" in the "Delete Private Data" window does not delete webfonts; this is why you have to do the above procedure manually.

You can use a program (for example CCleaner), batch file, or script to automate the procedure.

Workarounds

If having to delete the webfont cache periodically annoys you, you can do one of the following:

• Disable webfonts by unchecking "Enable Webfonts" in opera:config's "User Prefs" section.
• Disable the disk cache. This conserves disk space and might actually make Opera faster if your network connection is faster than your hard disk, or if you have a large enough memory cache.