No valid disc decryption key was found

When you're trying to decrypt an ISO

If you get this error using virtual DVD/Blu-ray drive and an ISO file, you're on your own. This use is not supported. Please do not ask for help.

When you're trying to dump physical blu-ray disc

Using PS3 Disc Dumper with PC drive requires a known public disc key to be available for your specific version of the disc.

PS3 Disc Dumper can automatically search for known public disc keys in multiple sources when you have a working internet connection, but not 100% of all discs have been preserved. In such cases your only other options are to either wait for your disc to be dumped by preservation groups, or to use a PS3 optical drive (primarily using a PS3 with CFW or HEN).

If you have access to the disc key that's not public, you can put it inside PS3 Disc Dumper key cache (⚙️ > Disc key copies will save to > Open folder) and restart the program, it will be checked and used automatically if it matches the disc.