How to Fix 3D Printer Not Reading SD Card – Ender 3 & More


3D printers like the Ender 3 can have issues with reading the SD card, making it difficult to actually get some 3D prints started. I decided to write an article helping you try and fix this issue.

To fix a 3D printer not reading the SD Card, you should ensure that the file name and folder are formatted properly and without spaces in the G-Code file. Inserting the SD card while the 3D printer is off has worked for many. You may need to clear up space on the SD card or replace it altogether if it is damaged.

There’s some more useful information that you’ll want to know with your 3D printer and the SD card, so keep reading for more.

How to Fix 3D Printer That Won’t Read SD Card

There are many reasons why your 3D printer might not successfully read your SD card. Some fixes are more common than others, and in some cases, you might have a major fault.

In most cases, the issue is related to software while in some cases, hardware such as the MicroSD Card itself or SD Card Port could also be at fault.

Below are some of the most effective solutions to apply if your 3D printers are not reading SD cards.

  1. Rename the File
  2. Remove Space in G-Code File Name
  3. Insert SD Card with Power OFF
  4. Change the Format of SD Card
  5. Try Using SD Card Under 4GB
  6. Put Your SD Card in the Other Way
  7. Fix the Connections of the Card Reader
  8. Clear Up Space on Your SD Card
  9. Replace Your SD Card
  10. Use OctoPrint to Get Around Needing an SD Card

1. Rename the File

It is a standard for most 3D printers such as the Ender 3 that the g-code file currently uploaded in the SD card should be named within the 8 characters limit. Many people have claimed on Reddit forums and in YouTube comments that they were having the same issue of a 3D printer not reading the SD card.

When they renamed the file and mitigated the characters within the 8 characters limit, the issue was resolved without requiring a second try. If you have saved the g-code file with a name bigger than 8 characters, the printer may not even display the SD card as inserted.

Another thing to keep in mind is to not have a folder with underscores in the name because it can cause reading issues.

2. Remove Spaces in G-Code File Name

Almost all 3D printers consider spaces as an unidentified character.

This could be the reason for your 3D printer not reading the SD card because if the G-code file name has spaces in between, the printer may not even recognize it while showing an immediate SD card error message.

So, one of the first things you should do is to name the file without any spaces and if there are any, rename it and insert the SD card again to test if it works. Some of the other things to keep in mind are:

  • The name of the G-Code file should only begin with a letter or a number instead of an underscore or any other character.
  • The G-Code file in the SD Card should not be a subfolder as some printers don’t give access to these subfolders.

3. Insert SD Card with Power OFF

Some 3D printers won’t detect an SD card if you insert it while the printer is ON and working completely. Some people have said that you should turn the 3D printer OFF before inserting the SD Card.

They suggested going with the procedure as follows:

  1. Turn OFF 3D Printer
  2. Insert the SD Card
  3. Turn ON 3D Printer

One user suggested hitting any button if you are facing an SD Card Error Message. This practice can redirect you to the Main Menu where you can click on the “Print from SD Card” and then OK. This can solve the card reading issue in many cases.

4. Change the Format of SD Card

It is highly recommended that you should only use an SD card with a format of FAT32. Almost all 3D printers work best with this format while most of them don’t even recognize SD cards if it has any other format.

It is recommended to go with the procedure by opening the MBR partition table. You will have all the partitions listed there. Select the SD Card in the “Removable Disk” category. Simply change the partition format from exFAT or NTFS to FAT32. The step-by-step procedure to change format on your computer’s file explorer is as follows:

  1. Open “File Explorer” either by clicking on the “This PC” icon or searching “File Explorer” from Start Menu.
  2. All the partitions and external devices will be listed in the section “Devices and Drives”.
  3. Simply right-click on the SD Card partition and click on the “Format” option from the dropdown menu.
  4. A formatting window will appear with a sub-label “File System”. Click on this option and it will display a few different formats of the SD Card.
  5. Click on the “FAT32(Default)” or “W95 FAT32 (LBA)”.
  6. Now click on the “Start” button at the bottom. It will format the SD card while removing all its data and changing its file system format as well.

Once the format has been changed, re-upload your g-code into the SD Card and insert it into the 3D printer. Hopefully, it will not show an error and will start working properly.

5. Try Using SD Card Under 4GB

Although it is not common in all 3D printers, having an SD card of more than 4GB can also cause reading issues. Many users have claimed that you should only buy and insert an SD card within the 4GB limit when it is going to be used for 3D printers.

Look onto the SD card while buying and make sure it isn’t HC (High Capacity) as such kinds of SD Cards may not work well with many 3D printers.

No doubt this factor can cause errors, there are also users who claim to have used an SD card of 16GB without facing any issues. So, it mainly depends on different types of 3D printers and their compatibility.

6. Put Your SD Card in the Other Way

This one sounds obvious but some users managed to be inserting the SD card the wrong way. You may assume that your should be putting the SD card into your 3D printer with the sticker facing upwards, but with the Ender 3 and other 3D printers, it actually should go in sticker-side down.

In most cases, the memory card won’t be able to fit in the wrong way around, but some users have experienced this issue so it could be worth looking into for fixing your SD card reading issues.

7. Fix the Connections of the Card Reader

You might just have issues with the connections of the card reader inside your 3D printer. If you’ve ever looked inside a 3D printer, it has a mainboard that has a card reader built into it. That card reader part might have damaged connections which are leading to bad reading issues.

One user tried pushing in the SD card fully into the card reader the whole time and not allowing the spring recoil to occur that pushes the card out slightly. When he did this, he turned on the 3D printer and the card was recognized, but when he stopped applying pressure, the card stopped reading.

In this case, you may have to replace your mainboard or get the card reader connection fixed by a professional.

Here’s a video that shows a MicroSD card slot repairing.

You would get something like the Uxcell 5 Pcs Spring Loaded MicroSD Memory Card Slot from Amazon and replace it, but it does require technical skills with a soldering iron. I’d recommend taking it to a repair shop if you choose this option.

8. Clear Up Space on Your SD Card

Depending on the quality of your SD card and the reading ability of your 3D printer, even when your SD card isn’t full, it may still cause issues of being read. An SD card that has several large G-Code files or just a large number of files might cause issues reading.

I think this can also be affected by your firmware and motherboard of your 3D printer

9. Replace Your SD Card

If your SD card has gone through some physical issues like the connectors being damaged or there is some other type of issue, you might just want to replace your SD card altogether.

I’ve had some instances where my 3D printer read the SD card perfectly, but all of a sudden, the SD card just stopped being recognized by my 3D printer and my computer. I tried removing and inserting it many times but nothing worked out, so I just had to replace the SD card.

When you are removing your SD card from your computer or laptop, make sure you press “Eject” so it is ready to be taken out. Removing the SD card with haste can cause some technical issues. You don’t want to have half-written data on your SD card by removing it without properly ejecting it.

Many people mention that the SD cards that come with 3D printers aren’t the best quality so you may run into issues if that’s the SD card you are using. This isn’t the case all the time, but it’s worth keeping in mind.

10. Use OctoPrint to Get Around Needing an SD Card

Using OctoPrint is a great way to bypass the need of an SD card since you can wirelessly transfer files from your computer or laptop to your 3D printer. Several 3D printer users love this method of transferring files since it makes things simpler and gives plenty of extra functionality.

How to Configure an SD Card for 3D Printing

There are a few steps on how to configure an SD card for 3D printing:

  1. Start by formatting the SD Card before saving a G-Code file in it, making sure the SD card is clear except for the bin file
  2. Set the file system or format of the SD Card to “FAT32”.
  3. Set the allocation unit size at a minimum of 4096 Bytes.
  4. After setting these factors, all you need to do is simply upload the G-code file into the SD card and then put it inside the SD Card or USB port on the 3D printer for further processing.
  5. You may need to re-format the SD card with the “Quick Format” box unchecked if the SD card is still not working

How Do You Use an SD Card & Print in a 3D Printer?

Using an SD card in a 3D printer is a simple process once you understand what you are doing.

Here are the steps on how to use an SD card in your 3D printer:

  1. Once you have sliced your model in slicer software on your laptop or computer, insert the SD card along with an SD card reader in the USB port.
  2. Copy the G-Code from the slicer and paste it or save it into the SD card.
  3. You can directly send the model file into the SD card by simply clicking on the “Export Print File ” from the slicer’s menu and selecting the SD Card as the “Storage Location”.
  4. Make sure that the g-code transfer has been completed successfully before pulling the SD Card out of the port.
  5. Insert the SD Card into the SD Card port on your 3D printer. If there is no slot for SD Card, use a USB card reader for this purpose.
  6. As soon as the card is inserted, the printer will start reading the files and become ready to print your model.
  7. Now select the “Print from SD Card” option from the 3D printer’s small LED screen.
  8. It will open up the files on the SD Card. Select the file you have just uploaded or want to print.
  9. That’s it. Your 3D printer will start the printing process within a few seconds.

How to Format a MicroSD Card for Ender 3

The normal procedure of formatting an SD Card to remove its files has been discussed in the previous sections but you need some additional formation as well. In order to work on a 3D printer using an SD Card without facing any issues, you need to format the card to the FAT32 file system and set the partition table to the MBR also known as Master Boot Record.

Start by clicking on the “Start Menu” icon and then searching “Disk Management”. Open it by double-clicking on it. Disk Management may be labeled as “Create and Format Hard Disks Partitions” as well.

A window will open listing all the partitions and removable devices currently attached to the computer.

Right-click on the SD card (by recognizing it through its size or name) and select the “Delete” option. This will wipe off all the data while deleting the storage partition as well. The SD card storage will then be mentioned as unallocated.

Under the “Unallocated Storage” section, right-click on the volume of the SD Card and open its properties.

Click on the “Volume” button in the menu tab, it will show you the partition style line in the window.

If the SD Card is set as MBR by default, well and good, but if it is not, you need to set it to the Master Boot Record from “Command Prompt”.

Open the Windows PowerShell as an Admin and start typing commands one by one as follows:

DISKPART > Select Disk X (X represents the number of disks present, found in the Disk Management section)

Once it says that the disk has been selected successfully, type “convert MBR”.

Once you complete of the processing, it should show a message of success.

Recheck the SD Card properties to verify that it has been converted to MBR file type by right-clicking Disk Management, going to Properties, and checking the Volumes tab.

Now go to Disk Management, right-click the Unallocated box, select “New Simple Volume” and go through the dialogs until you reach the part that allows you to enable “Format this volume with the following settings”.

During the process, set the file system format as “FAT32” and you should now be ready to use the SD Card in your 3D printer.

You can check out this guide for formatting your SD card for Windows, Mac & Linux.

Does the Ender 3 V2 Come with an SD Card?

The Ender 3 V2 comes with a wide range of tools and equipment along with a MicroSD Card. You should receive an 8GB MicroSD card along with a card reader to help transfer files from your computer or laptop to the SD card.

The latest version of the Ender 3 series which is the Ender 3 S1 actually comes with a standard SD card which is the larger version.

Best SD Card & Size for 3D Printing

The SanDisk MicroSD 8GB Memory Card from Amazon is a great choice for your 3D printing needs. Most 3D printer G-Code files aren’t very large, so having 8GB from this reputable company should be more than enough to get you 3D printing successfully. A 16GB SD card is also popular but not really needed. 4GB can work well.

Some people actually have issues with larger SD cards like 32GB & 64GB, but after switching to an 8GB SD card, they don’t have the same issues.

Can You Take Out the SD Card While 3D Printing?

Yes, you can take out the SD card while 3D printing if the print is paused. Users have tested this and mentioned that when their print was paused, they copied files over, put the SD card back in, and resumed printing. One user even paused and made slight G-Code modifications to the fan speed and continued successfully.

Files in 3D printing are read line-by-line so that makes it possible, though you should be careful with doing this because you could potentially end the whole print if you can’t get it resumed. You may have to turn off the printer and turn it back on again to get a prompt to resume the print.

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