If you added a new emulator called Retroarch Arcade which is set to not unzip games, then you need to tell the games that. The "Default" checkbox in the manage emulator screen is for imports only, it wont change it after they are imported, you need to bulk edit your roms to use the other retroarch emulator. Click your arcade platform then a game in it, use CTRL A to highlite all the games in that platform and right click one and choose edit. This will open the bulk edit wizard, click next, in the first dropdown choose emulator and in the second dropdown that appears select your Retroarch Arcade emulator, finish out the wizard.