Drumline update

I have had some serious trouble updating/downloading the new Drumline update. And since I have updated the app all together I can’t use the Drumline portion to the extent that I was until I update it. However, ever attempt to update it has ended with an error message that says it can’t download on a “read-only storage: Macintosh HD”. Now while I understand this is a laptop problem, I have connected with Apple support on multiple occasions to somehow change my settings to something other than “read-only”. And every attempt with that has ended with no success. I’m confident that it is not a consistent laptop problem and that this extension shouldn’t be having this much trouble, and if it still persists then I will have to move to a different program as I write and teach for a living and I can not continue to have this happen. Like I said, I have contacted Apple multiple times with no success. I appreciate any help you can give, thank you for your time.