Why can’t i format my SD card Steam Deck?

The Steam Deck is Valve’s new handheld gaming PC. It allows you to install and play your Steam games on a portable device. One of the great features of the Steam Deck is that it has a microSD card slot, so you can expand the internal storage. Many users run into issues when trying to format microSD cards to use with their Steam Deck. There are a few common reasons why you may be unable to format an SD card for the Steam Deck.

SD Card Size Limit

One potential reason is that your SD card is too large. The Steam Deck has a maximum supported microSD card size of 512GB. If your card is larger than that, the Steam Deck will be unable to format it. So if you have a 1TB or larger SD card, it simply won’t work. You’ll need to use a 512GB or smaller card.

Using exFAT Instead of ext4

By default, the Steam Deck expects SD cards to be formatted using the ext4 file system. However, many large SD cards come pre-formatted with the exFAT file system instead. The Steam Deck does not recognize exFAT SD cards. So if your card is already formatted as exFAT, you’ll need to connect it to a Windows, Mac, or Linux PC and reformat it to ext4 first.

SD Card Errors

Sometimes there may be underlying issues with your SD card that prevent proper formatting. If the card has physical defects or file system errors, the Steam Deck will be unable to format it. You may need to test the card in another device like a PC to check for errors. Use the native disk utility in Windows, Mac, or Linux to scan for bad sectors. This can identify if the card is damaged.

Trying to Format via the SteamOS Interface

The Steam Deck’s onboard SteamOS interface provides an option to format SD cards. However, some users report issues when trying to format cards this way. Instead, it is more reliable to format SD cards from an external PC before using them with your Steam Deck. Use the native disk utility on Windows, Mac, or Linux to reformat the card to ext4.

Poor Quality or Fake SD Cards

There are many counterfeit and low quality SD cards being sold. These cards often don’t meet their advertised specs and can exhibit odd behaviors. If you purchased an SD card from an untrustworthy source, it could simply be defective or fake. Stick to reputable brands like SanDisk, Samsung, Kingston when buying SD cards. Avoid sketchy wholesale sellers that offer SD cards at too-good-to-be-true prices.

Trying to Use SDXC Cards

The Steam Deck can be picky about compatible SD card types. SDXC cards with high capacities may not format properly. Although the Steam Deck supports up to 512GB, it is safest to use SDHC cards only. They are more likely to work. So if you have been trying and failing to get an SDXC card working, consider trying an SDHC one instead.

Incompatible Card Readers

If you are attempting to format your SD card using a reader connected to a PC, take note of the reader model. Some SD card readers are totally generic and have poor driver support. This can cause issues with reading, writing, and formatting cards. Use a named brand reader from the likes of Anker, Transcend, or Sabrent. And make sure to install the latest drivers.

Trying to Partition the SD Card

The Steam Deck only supports using the full capacity of an SD card formatted to ext4 in one partition. Trying to partition the card into multiple volumes or create multiple file systems on it will make the card unreadable by SteamOS. Stick to a single partition formatted as ext4 if you want your SD card to work properly.

Inadequate Power Delivery to the SD Card

High capacity SD cards require a certain amount of consistent power delivery to operate stably. Some low quality card readers and cables may not provide enough power. This could result in IO errors, disconnections, or failed formatting. If you suspect the SD card is not getting enough power, try formatting it directly in the Steam Deck itself or use a higher quality reader with its own power source.

Using Slow SD Cards

There are different speed grades when it comes to SD cards. While the Steam Deck can technically support cards of any speed, formatting is more likely to fail on very slow cards. Most Class 10 SD cards with U3 and V30 ratings should work fine. But older, slower cards may struggle. Test the card’s actual transfer rate in a PC to identify if the card’s low performance is an issue.

Damaged SD Card Contacts

If the physical gold contacts on your SD card are damaged, the Steam Deck will be unable to read, write, or format the card. Carefully inspect the contacts to check for any scratches, corrosion, or deformation. Clean the contacts gently with isopropyl alcohol if needed. But if they are permanently damaged, the card likely needs to be replaced.

Using Ultra Endurance SD Cards

Certain kinds of SD cards are engineered for extreme endurance at the cost of peak performance – likedashcam SD cards. The Steam Deck may have difficulties properly recognizing and formatting these types of cards. General use and high performance SD cards are recommended for the Steam Deck instead.

Running Low on Storage Space

The Steam Deck needs sufficient free storage space on its internal drive to complete the SD card formatting process. If your Steam Deck is almost full, it could fail to format an SD card. Check your available space and free up some gigabytes by deleting unneeded games or files before trying again.

Problems with the Steam Deck’s SD Card Slot

In rare cases, some Steam Deck units seem to have defective SD card slots from the factory. If you are sure your SD card is good but the Steam Deck consistently fails to read or write it, this points to a hardware flaw. You may need to RMA your unit to Valve for repair in that situation.

Using Non-Steam Games

While the Steam Deck is designed for Steam games, you can add non-Steam game shortcuts and launch them too. But some users report issues formatting SD cards if they are trying to install non-Steam games like Epic or GOG titles. For best compatibility, stick to Steam games only with your SD card.

Inconsistencies Between Versions of SteamOS

Valve is frequently issuing software updates for SteamOS to fix bugs and improve functionality. Sometimes issues formatting SD cards arise from inconsistencies between SteamOS versions. If your Deck was recently updated, check for a newer version of SteamOS that may address any SD card problems.


Formatting an SD card for the Steam Deck should be simple, but many users report frustrating issues getting cards working properly. There are a variety of potential causes including compatibility problems, hardware defects, software bugs, and user error. Following the recommended steps in this article should help eliminate most problems formatting and using SD cards with the Steam Deck. But if issues persist, seeking help via Steam Deck forums or Valve support may be necessary to resolve rarer bugs and defects. With some diligence, your external storage can work as intended.

Troubleshooting Steps

Here is a summary checklist of steps to troubleshoot SD card formatting issues on the Steam Deck:

  • Use 512GB or smaller SDHC cards
  • Reformat to ext4 file system if needed
  • Scan for errors and bad sectors
  • Use external PC for initial formatting
  • Purchase cards only from reputable brands
  • Use SDHC instead of SDXC
  • Try a different high quality card reader
  • Do not partition into multiple volumes
  • Ensure adequate power delivery to card
  • Avoid ultra slow or ultra endurance cards
  • Inspect for physical damage to contacts
  • Free up internal storage space on Steam Deck
  • Check for SteamOS updates and inconsistencies

Following this step-by-step checklist should help resolve most issues formatting SD cards for the Steam Deck.

SD Card Recommendations

Based on the criteria outlined in this article, here are some ideal SD card models recommended for use with the Steam Deck:

Brand Model Capacity Type Speed
SanDisk Extreme Pro 256GB SDHC Up to 170MB/s
Samsung EVO Select 512GB SDHC Up to 130MB/s
Kingston Canvas React 128GB SDHC Up to 170MB/s
PNY Elite-X 256GB SDHC Up to 100MB/s
Silicon Power Superior Pro 512GB SDHC Up to 170MB/s

These SD cards meet the size, format, speed, and compatibility requirements for optimal performance with the Steam Deck. Buying an SD card from a reputable brand like these will give you the best chance for success formatting and using expanded storage.