CS6 runs 100% offline. You don't need to "check in" with Adobe servers every 30 days. You can install it on a studio computer in a remote desert, and it will work forever.
Photoshop CS6 Full is a historic, unsupported product. While it was excellent in its time, seeking it now for a new installation is risky and likely illegal if downloaded for free. Modern alternatives provide better security, performance, and features without the subscription cost of Creative Cloud. photoshop cs6 full
This was the big shift. CS6 was the first version fully optimized for 64-bit processors. It uses the GPU (video card) to render liquify, transform, and warping in real-time. For full-resolution RAW files, this was a game-changer. CS6 runs 100% offline
Even with the "full" installer, errors happen. Here are the most frequent: Photoshop CS6 Full is a historic, unsupported product