Firstly, we can create a backup on a pc and wipe out device contents,
Security Options - General Settings - Menu - Wipe Handheld, and type password as "blackberry". The device will then restart. Now we need to reactivate BB,
Options - Advanced Options - Enterprise Activation,
You need a username and password to proceed. Username is your email address and re-activation pw can be generated through bb server by searching the user and right click and set Activation Pw. This should fix the issue.

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Take Complete Backberry backup using desktop Manager and wipe your handheld, then syncronize by doing enterprise activation, and restore backup.
Regards,
Mohammed Abid Razvi
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The first step before wiping the Blackberry is to remove the battery for 20 sec. put it back and check the sync again. While all other steps are correct, most BB issues will be resolve by a hard reset.
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