This guide will teach youdemonstrates how to use SAFE_MODE, a 3ds family recovery feature which canable to fix damaged system titles, as well as other software/firmware issues. It's demonstrated here on a 2ds2DS XL, but the process is the same for all 3ds family systems
Conclusion
If safe mode did not solve your issue, you may need to do a system format. Keep in mind, though,this will delete all user data from your console
If your issue persists after following this guide, a system format may fix it. Or, if you'd prefer to keep your data, you can post a question in the [link|https://www.ifixit.com/Answers|Answers Forum|new_window=true]