You receive the following error on the handheld:

Decryption failure. Please regenerate key.

Summary of Causes
The decryption error occurs for one of the following reasons:

The encryption key information on the handheld differs from the key stored on the BlackBerry Enterprise Server or BlackBerry Desktop Redirector. If you purchased the BlackBerry Wireless Handheld from a previous user, a second service, set up by that previous owner, might be sending data to the handheld.

Resolution 1
Generate a new encryption key with one of the methods below.

From the handheld
1 - On the handheld, click Options > Security.
2 - Scroll down to the Services section.
3 - Click the trackwheel and select Regenerate Encryption Key.

With Desktop Manager
1 - Connect the handheld to the computer hosting your desktop software.
2 - Open Desktop Manager.
3 - Double-click Redirector Settings. The Redirector Settings window appears.
4 - Click the Security tab.
5 - Select the Generate keys manually option and click Generate. The Generating New Key dialog appears. Move the mouse randomly to generate a new encryption key.
6 - Click OK.

From the BlackBerry Enterprise Server
1 - Connect the handheld to the BlackBerry Enterprise Server.
2 - Right-click BlackBerry Manager and select Properties.
3 - Click the Port tab, and select COM or USB for the handheld connection. Or to find the handheld automatically, click Detect. A window appears asking you to ensure that the device is connected. Click OK.
4 - A window appears indicating the handheld was found and the personal identification number (PIN). Click OK.
5 - Right-click the user’s account and choose Properties.
6 - Click the Security tab and select Generate keys manually.
7 - Click Generate and move the mouse around.
8 - Click Apply to change the status from Pending update to Up to date. Click OK.

With Enterprise Activation
1 - On the BlackBerry Enterprise Server, right-click the user account and select Properties. The Properties window appears.
2 - On the General tab, click Set Activation Password. The Set Activation Password window appears.
3 - Type an activation password and click OK.
4 - Click OK to close the Properties window.
5 - On the handheld, click Options > Enterprise Activation.
6 - Type the user account email address in the Email field.
7 - Type the enterprise activation password in the Password field.
8 - Click the trackwheel and select Activate.

Resolution 2
Check if the handheld is receiving data from another service provider.

1 - On your handheld Home screen, click Options and select Status to find your personal identification number (PIN).
2 - Write down your PIN.
3 - On the Home screen, press the Alt key and enter LGLG. The Debug Log screen opens.
4 - Scroll down and stop on the following line which appears in bold:

E net.rim.gme – RDKf-CMIME:<PIN>$<SUID>

PIN is your handheld personal identification number and SUID is the Specified User ID of the service sending you the data--a service relay protocol (SRP) identifier for a BlackBerry Enterprise Server or an email address for the BlackBerry Desktop Redirector.

5 - Click the trackwheel. From the menu, select View Event to see detailed information about the event.
6 - Write down the SUID information.
7 - Press the escape button to exit the Debug Log screen.
8 - On the handheld Home screen, click Options and select Service Book.
9 - Scroll down and stop on Desktop [CMIME].
10 - Click the trackwheel and select View.
11 - Compare the UID field with the SUID information you wrote down in step 6. If they differ, you are receiving data from another service provider.
12 - Contact the previous owner so they can disable their service.