Issues with SD cards is something I see comes up constantly and there is no good answer as each printer is a bit different but I will try and cover some of the more common issues people encounter.
Card formatting:
Most printers want the format to be FAT32. When you format a card this is what you want to select. Best option is to do this with the printer if it has the option. That way it will for sure do it correctly. If you need to do it on your computer how you do it will depend on your operating system be it Windows or MacOS. More recent versions of Windows are defaulting to ExFat for the file format which is not compatible with a lot of printers. The reason for this is because FAT32 is only capable of file system sizes up to a point and newer devices are having storage systems larger than that. You will loose everything on the card when formatting it.
Card Size:
Older/cheaper printers typically use 8bit boards. This can have a limitation on how big the SD card partition can be. This can vary depending on which firmware your printer is using but in general you want to stick with 16GB and under cards. Or if you have a larger card such as a 256GB card, create only a single 16GB Fat32 partition.
Card failure:
To save money printer manufactures use some pretty cheap SD cards. The storage chips in SD cards can only handle being written to so many times before they fail, the cheaper the card typically the quicker they die.
Corrupted file system:
You may have seen your OS complain about you not ejecting a USB stick or SD card when taking it out. The reason for this is it can cause corruption if you do not eject the media via the operating system first before pulling out the storage device. The fix for this is to format the card again, you will loose everything on the card when doing this.
File name too long:
Especially with older printers and sometimes with newer ones file names can be too long for your printer to understand. If you find you can see certain files the names of the ones you can not see might be too long. This amount varies depending on many variables in the firmware so an exact number is not easy to say.
