Thanks for your interest in using DSSR. Your screenshot provides information that explains why you're having problems using DSSR.
You're on a macOS, and you have double-clicked the
x3dna-dssr executable to run it. I can reproduce your case by installing
x3dna-dssr under the
~/Downloads folder and double-clicking it. The error message is quite informative, by showing
that x3dna-dssr is run, and immediately exit. Running
x3dna-dssr without any options gives the following message:
missing required option: must specify -i=PDBFile/mmCIF
type: 'x3dna-dssr -h (or --help)' for further help
'x3dna-dssr --citation' for preferred citation(s)
Time used: 00:00:00:00
That means DSSR is already successfully installed on your macOS. It is just that DSSR is a command-line (CLI) program, and you need a terminal window to run it. There are many online tutorials on how to get started using terminal on macOS. Here is one:
Absolute BEGINNER Guide to the Mac OS Terminal. Once you are familiar with the terminal, running DSSR should be straightforward, as detailed in the User Manual.
The DSSR executable (x3dna-dssr for macOS and Linux, and x3dna-dssr.exe for Windows) is self-contained and does not rely on any third-party libraries. There is no need for any setup or configurations: type x3dna-dssr -h to verify your installation. Note that DSSR is a command-line program: you need a terminal window to run it.
If you're GUI-driven and do not want to use CLI at all, then you may find the following two resources helpful:
Best regards,
Xiang-Jun