What Can Cause the Ender 3 (Pro/V2) Not to Read the SD Card?

When we think of a universal digital storage medium, SD cards are undoubtedly the first things that come to mind, considering that whether you’re using a smartphone, a digital camera, a handheld gaming console, or a computer, it’s possible to utilize an SD card to store and transfer data between devices.

On the other hand, the SD card technology is not immune to problems either, as, similar to any other form of storage, software factors, such as the filesystem being used, also play a vital role in the compatibility between an SD card and the device that is supposed to access it, which can create minor issues along the way.

In today’s article, we will be diving into the particular issue of the Ender 3 not being able to access the SD card, which, as a result, makes it impossible to start the printing process due to the 3D printer not being able to access the G-code file contained within.

So, what can cause the Ender 3 not to read the SD card?

Below, you can find a list of the potential culprits behind the issue of the Ender 3 not reading the SD card:

  • Incorrect SD card filesystem or partition table
  • Corrupted SD card filesystem
  • Filename-related problems
  • Uninitialized SD card
  • Directory-related issues
  • Usage of an SD card with too high capacity

Next up, we will further examine the factors that can prevent your Ender 3 from reading the SD card, find out how to fix the issue at hand as quickly and efficiently as possible, go through the process of formatting an SD card for usage with the Ender 3, and finally, discuss how to choose a compatible SD card for the Ender 3.

What Can Cause the Ender 3 (Pro/V2) Not to Read the SD Card?

Even though there are ways to start a print without utilizing an SD card, printing with an SD card is the method that most 3D printing enthusiasts use due to it being the default way that does not require any extra setup, which makes the Ender 3 not reading the SD card a critical problem.

Here are the most common reasons that can prevent your Ender 3 from correctly reading and accessing the SD card:

  • The SD card is formatted with an incorrect filesystem or partition table. The correct filesystem and partition table combination for the Ender 3 to detect the SD card is FAT32 for the filesystem and MBR for the partition table.
  • The SD card filesystem is corrupted. SD card filesystem corruption can stem from various causes, ranging from frequently switching the card between different devices to removing the card while a device is still accessing it.
  • The filenames used for the G-code files are not readable. As a rule of thumb, filenames that are too long or contain special characters, accented letters, and spaces can create situations where your Ender 3 cannot read them.
  • The SD card is not initialized. While the SD card should automatically be initialized when you turn your Ender 3, inserting the SD card while the Ender 3 is already powered can create a scenario where manual initialization is required.
  • The directory paths used for the G-code files are inaccessible. In some cases, the Ender 3 may not be able to reach the folders other than the root directory for various reasons, causing the G-code file to become inaccessible.
  • The capacity of the SD card is too high, making it incompatible. Even though there is no official information about a capacity limit for the SD card, there are many reports in the 3D printing community about the Ender 3 not reading SD cards that are larger than 8 gigabytes.

How to Fix the Issue of the Ender 3 (Pro/V2) Not Reading the SD Card?

Fortunately, in most cases, the issue of the Ender 3 not reading the SD card should be easily solvable, as it mostly comes down to minor oversights on the software side that can be fixed without the need for too much technical expertise.

Below are the steps we recommend following to fix the issue of your Ender 3 not reading the SD card and get things operational once more:

  1. Insert the SD card into your computer.
  2. Convert the partition table of the SD card to Master Boot Record (MBR). Please note that all the data on the SD card will be wiped following this step.
  3. Format the SD card, ensuring that you have selected the FAT32 filesystem.
  4. Copy the G-code file you would like to print to the root directory of the SD card without creating any extra folders.
  5. Rename the G-code file so that it does not contain any special characters on spaces and less than ten characters.
  6. Power your Ender 3 off.
  7. Remove the SD card from your computer and insert it into the Ender 3.
  8. Power on your Ender 3.
  9. Initialize the SD card through the LCD interface if the SD card is not automatically detected.

How to Format an SD Card to Use in the Ender 3 (Pro/V2)?

As formatting the SD card you intend to use with the Ender 3 is a process where even the slightest of errors can prevent the Ender 3 from correctly reading the SD card, it’s vital to ensure that you follow the correct methodology.

While the exact procedure that you will need to follow to format an SD card will vary depending on the operating system you’re using, there are two primary aspects to take into account for successfully formatting an SD card for usage with the Ender 3, regardless of how you conduct the formatting process.

The first condition for the Ender 3 to be able to access an SD card is the usage of the FAT32 filesystem during formatting, which, the default tool for formatting, regardless of the operating system you’re using, should allow you to choose before you initiate the process.

The second condition, which is the one that is more likely to be overlooked due to it not exactly being a part of the formatting process, and as a result, not showing up on the interfaces of formatting tools, is the usage of the MBR (master boot record) partition table and not the GPT (GUID partition table) for the SD card.

To switch the partition table, you will need to use the disk utility tool of the operating system you’re using in most cases, such as Disk Utility in macOS, diskpart in Windows, and gdisk in Linux.

Once the SD card is configured in a way where both of these conditions are fulfilled, your Ender 3 should be able to read it without any issues, regardless of the device or the tools you have used for the formatting process.

How to Choose a Compatible SD Card for the Ender 3 (Pro/V2)?

Even though the Ender 3 should technically support all SD cards, as there are no official specifications about SD card selection, there are reports in the community about the Ender 3 not being able to read SD cards that exceed a particular size.

Our recommendation would be to go for a microSD card with a capacity of 8 gigabytes or less for the purposes of usage with your Ender 3, preferably from a reputable brand, to avoid any potential issues that may arise from factors such as defects that stem from the manufacturing process.

Please note that our recommendation only applies if you’re having problems with the current SD card you’re utilizing or if you haven’t bought an SD card for your Ender 3 yet, as there is not much of a reason to replace an SD card that is already functioning correctly.

Wrapping Up

Except for the rare cases where the SD card itself or the SD card slot of your Ender 3 is damaged, the issues that can prevent the Ender 3 from reading the SD card are pretty uncomplex, meaning that you should be able to get back to your prints in no time.

To quickly recap, filesystem or partition table incompatibility, filesystem corruption, problems related to the naming and the pathing of the G-code files, the SD card simply being uninitialized, or even something as odd as the usage of an SD card with too high capacity can cause the issue of the Ender 3 not reading the SD card.

While the procedure to fix the problem of your Ender 3 not reading the SD card can seem slightly technically challenging at first glance, especially if you don’t have a lot of expertise with computers, the process is reasonably straightforward once you know the exact steps to take.

Happy printing!