Despite what Adobe is saying officially, Photoshop 2021 does NOT require support of SSE4.2 to run. The real problem is that: - IPP libraries optimized for SSE3 are missing from distribution (they are available from Intel) - OpenCV library was build with SSE4.2 requirement To fix this download this pack of libs from any source below (it's the same): https://www113.zippyshare.com/v/cqtznzt2/file.html https://www.sendspace.com/file/vh0wjm Unpack archive and copy libs to Photoshop 2021 installation directory (overwrite opencv_world440.dll when requested).
This fixes the problem an PS runs just fine. But disclaimer as usual - all this at your own risk.
Please note that this is not a hack or something like this - this is official libraries from official sources. Intel IPP libraries was taken from Intel Parallels Studio XE 2020.1.0 and contains valid signature from Intel. OpenCV library was taken from official release of OpenCV 4.4.0 on GitHUB (https://github.com/opencv/opencv, build by VC15).