I deleted the majority of Garageband instruments and sounds and then I wasn’t able to re-download them for whatever reason. I deleted the file “Logic” in the directory, Computer > Library > Application Support, thinking those files applied only to Logic Pro X. I couldn’t save or load Garageband projects and it was horrendously slow. At the time, I had maybe 2-3GB of storage space left and my computer was essentially dysfunctional.
Just a few months back, I was rooting around in my computer’s directory trying to find files to delete.