.7z files and how to get them to work in retropie

[axis_D]

Hi all, I have several roms with a .7z extension. I'm using a mac and Unarchiver to unzip them, which converts them into files with an "sms" extension for the sega master system. When i move the file into the sega master system folder in retropie however it doesn't work. It appears on the menu screen, but it tries to load and just fades back out to the menu screen. So for example i have a filed called "20-em-1.7z".. i unzip it and it turns into "20-em-1 (b) [!].sms". I put that ".sms" file into the sega master system folder, but it just doesn't work. Any ideas on how to fix that? Thanks in advance.

[MuppetMikey]

i believe that retropie handles zip files.. have you tried to leave them zipped and then put them into the folder? they may also be a bad download..