Problem:

If you encountered the error when trying to install/uninstall an application, you may be facing a corruption in the registry where the keys missing or partially missing.

The installation source for this product is not available. Verify that the source exists and that you can access it.”

Solution:

At first it seemed to be affecting that specific application (Kaspersky Anti-Virus in my case) but later I found that it affected partner applications like the Network agent responsible for remote administration and monitoring. This was because the registry for that product id in the registry was corrupted to the point that Windows thinks it is installed and uninstalled at the same time so trying to do either results in a fatal error.

To avoid wasting time, rebooting Windows will not help resolve the problem since the registry itself is corrupted and it will get reloaded anyways on every reboot. Instead it is required to fix the corruption by visiting the respective page

http://support.microsoft.com/kb/971187

Note, the above link applies only to the following operating systems:

• Microsoft Windows XP Home Edition
• Microsoft Windows XP Professional
• Microsoft Windows Server 2003, Web Edition
• Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
• Microsoft Windows Server 2003, Standard Edition (32-bit x86)
• Windows Server 2008 Enterprise
• Windows Server 2008 Standard
• Windows Web Server 2008
• Windows Vista Business
• Windows Vista Enterprise
• Windows Vista Home Basic
• Windows Vista Home Premium
• Windows Vista Starter
• Windows Vista Ultimate

There is an automated way of fixing the issue (“Diagnose and fix the problem automatically”) and a manual way, I would recommend using the former option if you are not familiar with editing the registry and don’t want to make things worse.

Before proceed though regardless of the method you chose, I would recommend taking a backup of your registry using the following link http://support.microsoft.com/kb/322756

Simulation of the solution

Here you would select the problem you are facing.

Then select the problematic program

Finally Select the action you want to take

That should fix the error message “The installation source for this product is not available.”, if you have any questions or concerns please leave a comment below. You can also follow me on Twitter, add me to your circle on Google+, or like my Facebook page to keep yourself updated on all the latest of Hardware and Software reviews.