If you follow my Twitter feed, you saw me warning people about a possible glitch with the App World update from 126.96.36.199 (which I shall call x.33 from here out) to 188.8.131.52 (yeah, um, x.35 it shall be!).
I accepted the update - hey, App World itself offered it! - and immediately lost all access to App World. I did a battery pull reset, but to no avail (that's the ultimate solution to most BlackBerry problems...with the power on, remove the back cover and knock the battery out by tapping the phone on the edge of your hand, and no I'm not kidding). I looked around to make sure it wasn't buried in a folder somewhere. I uninstalled it and reinstalled it a number of times.
Finally I visited the RIM Community Support Forums. It was there that I saw this gigantic message thread. While it was comforting to see that I was not alone and hundreds of others around the world were reporting the problem, no solution was being proposed. I saw a message where some guy said he received an update notice to the BB OS itself, installed that using BB Desktop Manager, and his icon returned.
I figured what the heck, I didn't have an update to install but you can reinstall the same version again if you want. Just click Application Loader and when it shows you your choices, the most recent one will be checked. The upgrade process will back up your data and third party apps, so the most you will lose is some preferences and the occasional key for the purchased app. (Which, assuming App World returned, I would have no problem retrieving!)
It worked. The App World icon returned to my desktop, just where I'd put it back when I was running the x.33 version. In a massively ironic moment, Verizon Wireless then pushed an ACTUAL update to the BB OS (from 184.108.40.2062 to 220.127.116.112 - don't you love BlackBerry version numbers always looking like IP addresses?). So I had the privilege of repeating what I'd just spent an hour doing.
After returning to the support forums, I saw a post from one of the forum gurus that RIM was advising a "Security Wipe" (Options > Security Options > Security Wipe) to fix the problem. Right under that post was a message from a guy saying he'd tried it and App World was back, now where was his data and all his other apps? Here's a pro tip for you: Make certain you backup your data AND your third party apps because a Security Wipe means "delete everything on this BlackBerry and reload the basic software."
If you're not sure what I'm talking about, here's a post I made back in April that will walk you through it step by step. I feel bad for the guy who killed his BlackBerry, but come on! If the phrase "security wipe" doesn't clue you in to the fact that stuff is going to be erased, I don't know what will. But I also want to slap the guru for not including the simple warning to backup everything.
Here's the bottom line. RIM didn't really FIX anything. All they did was tell you to "reformat and reinstall Windows," to borrow a line from our buddies in Redmond. Will it work? Absolutely it will. Do we know what caused the problem in the first place? Not a clue.
Go ahead and update to the x.35 version of App World. It might work fine for you. But know that if your icon disappears, you get to spend an hour (or more, depending on how many apps need to be set up again) reformatting your BlackBerry. Oh, final note, don't worry about pictures, songs, or anything stored on your media card. None of these processes disturb anything on the media card.