Extensions not updating on MacOS Catalina (v10.15.1)

In an attempt to install the Musescore Drumline extension, the following message appears when attempted: "Cannot import extension on read-only storage".

Steps to reproduce my issue:

1) Have a Macintosh Computer running version 10.15.1
2) Launch Musescore
3) In the Menu Bar, under "Help", select "Resource Manager..."
4) Under the Install/Update column, press install or update depending on which one is present
5) Receive error message