Logged in as Guest user on my friend's Mac - this is what I get.

[petrucci666]

Weird font for 'Finder' and upper right corner on the Menu bar looks messed up.

Running Mavericks.

 

[djtech42]

Did they install any menubar customizations?

 

[petrucci666]

Nope, everything is stock Mavericks.

 

[Madd the Sane]

It looks like you have a missing or corrupt font. Maybe the guest account doesn't have permission to the system and local "Fonts" folders?

 

[petrucci666]

It looks like you have a missing or corrupt font. Maybe the guest account doesn't have permission to the system and local "Fonts" folders?

I'll look into it, but that shouldn't be the case. Pre-Mavericks, I logged in as a Guest on the very same laptop and it worked fine.

 

[Madd the Sane]

Perhaps Mavericks messed up the permissions?

If you are more technically-inclined, I'd file a bug report at bugreport.apple.com. If not, then at OS X's feedback page.