Not too long back, RIM released the 1.1.0.35 version of BlackBerry App World. I received a notification inside my messages inbox for the update and without much thought, I upgraded via the link provided in that notification message. After successfully installing, a routine reboot was done and my BlackBerry App World icon never showed up since then although it is displayed under the list of installed applications. I was then shocked to find out that the only solution to this problem for the time being is by doing a device wipe and restoring it back in order for it to show up. So, quit doing battery pulls or countless times of re-installation, it won’t work!

Workaround

To get the BlackBerry App World icon to reappear, complete the following steps:

1. Back up the BlackBerry smartphone by following the instructions in KB12487.
2. Delete all data and applications from the BlackBerry smartphone using the Wipe Handheld option by following the instructions in KB14058.
3. Restore the data from the backup taken in step 1 by following the instructions in KB10339.

Note: When the Wipe Handheld option is used, all data on the BlackBerry smartphone is erased. This might affect sending and receiving email messages. If the BlackBerry smartphone is associated with a BlackBerry Enterprise Server, complete the enterprise activation process to restore messaging functionality.

Source: BlackBerry Technical Solution Center