If you have already purchased and registered Adobe Creative Suite 5 (CS5) Master Collection, you can legally find your serial number using one of the following official methods. 1. Check Your Adobe Account
A serial number is required to activate and use Adobe Master Collection CS5 legally. Here are the legitimate ways to obtain a serial number:
Check Your Email or Product Packaging: If you've purchased a physical copy or a digital version from Adobe or an authorized reseller, your serial number should be provided in a confirmation email or on the product packaging.
Adobe Creative Cloud: The modern successor to CS5. It is subscription-based but ensures you have the latest tools and full compatibility with high-resolution displays and new OS versions.