I just upgraded to 4.5OS on my 8830, and all my non custom ring tones are gone. I use some of the chimes etc for text notifications etc. The ONLY ring tone I have showing is the single custom THX ring mp3 I use for my main ringer.
Unfortunately I'm on my phone right now, but someone has a link to the specific file in the forums somewhere so you don't have to do the whole download an older version/rip the file process. I downloaded it last night fine.
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