Two days ago I made my account a Jagex account and used HDOS from the launcher with no issues. Now, HDOS suddenly does not appear in the launcher, only RuneLite and the regular client. I tried uninstalling and reinstallling HDOS to no avail.
This completely ends the process which allows you to start the program on a clean slate.
If you just "exit" the program, it will still run in the background.