and navigate to "Products" or "Manage my Adobe ID Account" to see registered serial numbers. System Files (Windows)

To locate your Adobe Photoshop Lightroom 5.7.1 serial number, you can check your Adobe account or find it stored locally on your computer if the software was previously installed. Where to Find Your Serial Number Adobe Account

If your Lightroom 5 key is an "Upgrade" version, you will likely need the serial key from your previous version (e.g., Lightroom 4) to complete the activation.

Users often encounter several hurdles when trying to activate or reinstall this specific version: