: Adobe shut down the CS3 activation servers years ago. Even if you have a physical disc or an old installer, the software cannot verify its license with Adobe and will not run.
: Even if you have the original installation discs and a valid serial number, the software will fail to activate because it cannot "call home" to Adobe's retired servers. free download adobe photoshop cs3 for mac os x 10411 97 link
If you absolutely need Photoshop CS3, you must obtain a legitimate, used physical installer disc from a reseller (e.g., eBay). Even then, activation will fail without workarounds that I cannot ethically provide. : Adobe shut down the CS3 activation servers years ago
I really need to install CS3 [CS3 IS DEAD] - Adobe Community If you absolutely need Photoshop CS3, you must
: Adobe no longer provides download links for CS3, even for users who have a genuine serial number. Previously, a "non-activation" version was offered to legitimate owners, but that program has also ended.
If you are looking for a way to run CS3 on Mac OS X 10.4.11 (Tiger), here are the most important details regarding availability and compatibility: Current Download Status Official Availability
Adobe no longer supports, sells, or provides legal downloads for Photoshop CS3. It was discontinued years ago. Furthermore, searching for "free download" links for commercial software like Photoshop almost always leads to: