This article explains why you might see the "The Cozmo App could not read files. Error: 3" message.
This error message may appear if you have downloaded, installed or updated the Cozmo app while using an SD card in your device. When launching the app, you will not get past the loading bar screen. Anki apps do not support devices with external memory (SD Cards, USB, etc.). See this FAQ for further information on compatibility.
- Restart your device
- Uninstall the Cozmo app. Note you will lose progress by doing this
- Remove the SD card
- Reinstall the app
- If the error persists, please repeat the steps and also clear your Google Play Store and Google Play Service cache and data before reinstalling the app