If your Switch doesn’t recognize the microSD card, start with basic troubleshooting. Power off the console, remove the microSD card, and reinsert it firmly into the slot—ensure it’s aligned correctly with the gold contacts facing down. Check if the card is formatted to exFAT (Switch’s required format): connect it to a PC via a card reader, open File Explorer, right-click the card, select 'Format', and choose exFAT. If the PC doesn’t detect the card, try it in another device (e.g., phone) to rule out a faulty card. Use a can of compressed air to blow dust out of the Switch’s microSD slot—debris often blocks recognition. Update your Switch’s system firmware to the latest version, as outdated software can cause compatibility issues. If the card is still unrecognized, test with a different microSD card—if that works, your original card may be corrupted and need replacement.