If your Switch doesn’t detect the microSD card, try these steps. First, power off the console, remove the microSD card (located behind the kickstand on standard Switch/OLED), and reinsert it firmly—ensure it’s aligned with the gold contacts facing down. Check if the card is formatted to exFAT: 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 compressed air to blow dust out of the Switch’s microSD slot—debris often blocks detection. Update your Switch’s system firmware to the latest version. If the card is still not detected, test with a different microSD card—if that works, your original card is likely corrupted and needs replacement. Use a reputable brand like SanDisk or Samsung for reliability.