How do you uninstall BlackBerry Desktop Software v4.2 when you don’t use it anymore? BlackBerry Desktop Software runs on your desktop PC, allowing you to add new software and upgrades，keep your desktop and smartphone data organized, manage your enterprise emails and so on.
For reasons, BlackBerry Desktop Software may not have been installed properly, which may cause the installation unavailable. So to remove all information related to BlackBerry Desktop Software in order to prepare the computer for a new installation of BlackBerry Desktop Software.

There are two ways to uninstall BlackBerry Desktop Software v4.2

First:
How to uninstall BlackBerry Desktop Software v4.2 with Perfect Uninstaller

1. Open Perfect Uninstaller
2. Click on the Special Uninstall button

3. Find out the BlackBerry Desktop Software v4.2 in the application list, and then click it.
4. Click Next(maybe twice), and then Finish
5. Restart your computer to completely uninstall BlackBerry Desktop Software v4.2.

The goods of this method: It is simple and easy to followed with and the removal is perfect.

Second:

How to manually uninstall BlackBerry Desktop Software v4.2

Step1. Uninstall BlackBerry Desktop Software application

Learn how to do it

Step 2: Remove the registry entries of BlackBerry Desktop Software

Caution: Backup your registry information first; it is easy to make your PC crash if you edit your registry list.
For Windows XP:
1. In Windows XP, from Start, and then click on Run.
2. Type “regedit”, then click on OK.

3. Now it opens the Registry Editor.

4. Click on Export Registry.
5. Select “All” option for backing up every key of registry.
6. Give a destination file (say Regbackup) and save it on to the Desktop.
7. You can easily navigate through the subkey if you know what you are looking for. Or, you can press “Ctrl + F” to locate the subkey that contains the value you want to edit. (F3 to Find Next)

8. Under this key, there will be the subkeys (some may be absent, which is normal)
9. Click on each Version key to find contents in the right-window pane.
10. Delete all the sub-keys inside.
HKEY_CURRENT_USER\Software\
HKEY_LOCAL_MACHINE\Software\
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall.
Note: The following may exist there. You can judge whether they are the ones to be removed by clicking on each of them. If the window displays BlackBerry Desktop Software on the right side, you should delete them.
a. {}
b. BlackBerry {}

11. From File menu, click exit.

For Windows Vista:
1. From Start, then type “regedit“.

2. Click on “regedit” on the search result to open the registry editor in Windows Vista.
3. Steps are the same as Windows XP (see above).

Step 3: Delete folders of BlackBerry Desktop Software
For Windows 2000 or XP
1. Open Windows Explorer.
2. From C:\Program Files\. Delete “Research In Motion” folder.
3. From C:\Program Files\Common Files\. Delete “Research In Motion, Pumatech Shared, and Pumatech Desktop Setup” folders.
4. In C:\Program Files\Common Files\, rename the “InstallShield” folder to “InstallShield_Old”.
5. From C:\Documents and Settings\\Application Data\. Delete “Research In Motion” and “BlackBerry Desktop” folders.

For Windows Vista
1. Open Windows Explorer.
2. From C:\Program Files\. Delete the “Research In Motion” folder.
3. From C:\Program Files\Common Files\. Delete “ Research In Motion” folder.
4. In C:\Program Files\Common Files\, rename the “InstallShield” folder to “InstallShield_Old”.
5. From C:\Users\\AppData\Roaming\ and delete the “Research In Motion” and “BlackBerry Desktop” folders.

For Windows 98 or ME
1. From Start, click Explore to open Windows Explorer.
2. From C:\Program Files\. Delete “Research In Motion” folder.
3. From C:\Windows\Application Data\. Delete “Research In Motion” folder.

Step4: Register the atl.dll file
The atl.dll file need registering with Microsoft® Windows® in order that BlackBerry® Desktop Manager can work properly.

For Microsoft Windows 98, ME, or Windows NT 4.0
1. Click Start > Programs > Accessories > Command Prompt.
2. Depending on your operating system, type the right things into the command prompt and press ENTER:
> For Windows NT 4.0, type cd c:\winnt\system32
> For Windows 98 and ME, type cd c:\windows\system
3. Type regsvr32 atl.dll and press ENTER. A message shows that the registration is successful.
4. Type exit and press ENTER.
5. Restart the computer to completely uninstall BlackBerry Desktop Software v4.2.

For Microsoft Windows 2000 or XP
1. Click Start > Run.
2. In the Run window, type regsvr32 atl.dll and click OK. A message indicates that the registration was successful.
3. Restart the computer to completely uninstall BlackBerry Desktop Software v4.2.
For Microsoft® Windows Vista
1. Click Start > All programs > Accessories
2. Right click on Command Prompt and select Run as Administrator.
3. In the Command Prompt window, type regsvr32 atl.dll and press Enter.
4. A message indicates that the registration was successful.
5. Restart the computer to completely uninstall BlackBerry Desktop Software v4.2.
The goods of this method: You have to do a long-time job but it is very effective.