The good news is that your micro SD card seems to be fine because it still can be mounted and seen in your Steam Deck. You can double-check the integrity of your SD card by connecting it to your computer to see if it can show up there. If the SD card can be mounted and show up, you can insert your micro SD card back into your Steam Deck and I will show you how to solve the micro SD card not showing in the Steam Deck problem.
If the SD card not showing up on your computer, here are some resources you can refer to:
- SD Card Not Showing up in Windows, Fixes & Causes
- How to Fix SD Card not Showing up, Reading or Recognizing on Mac
If your micro SD card doesn't show up on Steam Deck in Gaming Mode, try the following solutions.
Solution 1: Install games on the right path
Note: Before you download any games on your microSD card for the Steam Deck, the card should be formatted to EXT4.
1. Open Desktop Mode and then open Steam.
2. Check if your games are installed at ~/.steam/steam/steamapps/ or ~/SteamLibrary/steamapps/. If not, you need to re-download games to this location, and Steam should detect your microSD card.
Solution 2: Manually add your microSD card to Steam Library
1. Open Desktop Mode > Steam > Settings > Downloads.
2. Press Steam Library Folders and press on the plus icon.
3. Add your microSD card.
4. Go to Gaming Mode to see if it works. If this still makes no difference, try to restart your Steam Deck device and try again.
Hopefully, your SD card becomes visible in Gaming Mode in your Steam Deck now.
