Not enough disk space when trying to copy file, yet I've only used 13.21 gb on my computer

Make sure the actual Free storage space on the destination drive is larger than the size of the file(s) you are copying. You may need more storage on the destination than is used for those files on the source drive due to differences in how the file system allocates storage on different file systems....the size of the drives play a role as well.

Ignore the "Available" storage value the macOS shows nearly everywhere since it is very misleading. Unfortunately the actual Free storage space value is only shown in Disk Utility and within the System Profiler. Even the "Used" storage space value is misleading these days at least when using the APFS file system.

What file systems are used on the SD card and the external SSD?

Can you also post a screenshot of the error message so we can see exactly what is shown?

rainesumner wrote:

Yes that helped, thank you very much!

You're welcome.

I've attached a photo of the prompt. It's confusing because it is misleading as to me its saying I don't have enough memory on the computer. Why wouldn't the prompt say you don't have enough memory on the san disk instead.....

It implies the destination does not have enough room since that is where you are trying to place the data. For an Apple error message, this message is one of the more informative ones. Most are even more cryptic & confusing....some with only an error code that no one knows anything about.

However, due to the complexity of the APFS file system, the solution is not necessarily obvious.