I was running a setup script locally and just hit the following error:
Retrying due to: unexpected result: "rejected" - Some("Canister rwlgt-iiaaa-aaaaa-aaaaa-cai is already installed.\nThis is an internal error on the IC. Please report it to IC devs on the forum: https://forum.dfinity.org")
I realized it was because dfx was already running, with these canisters already installed (I hadn't stopped dfx and then started it back up with --clean). Maybe this error/case can be modified to just tell the user to restart a fresh version of dfx?