Check that the systems extensions are declared in the systemes_extensions.txt file

In order to be able to display the list of your games for a given system, it is imperative that ARRM knows the list of file extensions recognized by this system.

Your system names are those appearing in this module, which actually correspond to folders on your disk:

Recognized extensions appear in the textbox: Extensions: .zip;.7z

The association is done via the following file:

%appdata%\Nexouille Soft\arrm\database\systemes_extensions.txt

Access to this file can be done via the icon or via the Modify extensions allowed by system button in the Settings tab then Configuration Files tab

By default ARRM comes with a preconfigured file for most system names. But it is possible that your system names (folders) have different names than those declared in these files or that your FrontEnd supports other file extensions. You will therefore need to modify this file by adding your systems and the list of recognized extensions.

Example :

You have a system named a2600 for Atari 2600
It is therefore necessary that in the file: %appdata%\Nexouille Soft\arrm\database\systemes_extensions.txt, add this line:

a2600|.a26;.bin;.zip;.7z;.rom

When the modification is made, for ARRM to take the changes into account, you must click on the button: which is located under the to the right of the extensions textbox.

For more details you can read this wiki article: My system names are different or I want to add a system, how to scrape?