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

Solution: It makes sense that the MSI InstallSource is not accessible if it is located in the ccmcache folder and the MSI has been deleted from there. However, the main problem is when the installer is removed from C:\Windows\Installer.

Do not delete files from C:\Windows\Installer. The usual need to do this is to free up space, because over time, after installing many applications, the free space decreases. Instead of deleting the files or the entire folder itself to free up space, it is recommended to delete unnecessary/unused applications.

Another common cause of missing installers is that the vendor MSI installer does not cache itself at C:\Windows\Installer.