I previously had (and have installed on my Mac) PS Lightroom 3. I just bought a Leica, which comes with PS Lightroom 4. I decided to first update my PS Lightroom 3 software to 3.6, and didn't have any problems doing so. When I try to install PS Lightroom 4, however, I can't do so. The Adobe Photoshop Lightroom 4.pkg file isn't opening or running at all. Please advise.
What Mac exactly? Verify the system reqs: