I have upgraded to 3.6.8 since the problem started happening and there is still no changes.

Any ideas out there as to how I can fix this issue?

i was having the same problem, but solved it by downloading lucida Sans font here and overwriting it. Hope it works for you.

Not a great solution for web developers. Cant ask everyone to download a font to see a site correctly?

This is still a problem in 3.6.10. C'mon.

I also tried downgrading to 3.5 and it didn't fix anything.

From my experience, this Lucida/Firefox font problem only happens to Adobe CS4 users. True for you?

Nope, I have CS5 and a coworker has no CS anything installed. It happened right when the update to 3.6.10 occurred.

I have noticed that CS4 seems to be the culprit as well. Me and another coworker with the CS4 suite installed both have the problem. I just had another coworker upgrade to FF 3.6.10, he has no CS products installed, and the problem does not exist.

It looks bold for me too. I have FF 3.6.10, CS4 on Vista 64bit. IE and Chrome look fine. I have another PC with the same setup sans CS4 and Lucid Sans looks normal in FF.

Upgraded to version 4.0.1 and it's STILL a problem.

I also use CS4 - but all other major browsers still display properly even so.

Even IE6 displays the font properly.

It's not just that it displays in bold it also looks very patchy too.

Is anybody going to fix this, or is the answer just a lazy "don't use that font"?

Had the same problem with Firefox 4.0. I had previously installed Adobe CS4, now uninstalled and have CS5 instead. Fixed the problem by reinstalling the font. Google 'download lucida sans' and you can find the .ttf file easy enough. Here is the one I used: Lucida Sans Regular

Try Lucida Sans Unicode - it worked for me under Windows!

I believe this is caused by an ambiguity in font names. "Lucida Sans" is the name of a family of fonts, not a single font. Therefore, when a website specifies "Lucida Sans" the browser/OS will pick one of the fonts within the family. If the PC has Lucida Sans Regular, it will typically pick that. If it doesn't, it may pick one of the others in the family, e.g. bold or italic. A common cause of this seems to be the situation I had: Windows XP - shipped with Lucida Sans Regular. Windows 7 - no longer ships with Lucida Sans Regular Office 2007 - still ships with the additional Lucida Sans styles (italic, bold)

Therefore if you install Office 2007 on Windows 7, you will have the variations of Lucida Sans, but not the original Lucida Sans Regular. Under this situation, I had IE8 picking Lucida Sans Italic, though firefox somehow was picking something else. Perhaps Firefox got more robust recently?