While writing a Node.js app on Cloud9, I repeatedly see a red "Could not update source" popup at the top of my screen. Due to the vague nature of the error message, I don't know whether it refers to the saving of my project (which is working perfectly) or the updating of npm repositories (all of which are up to date) or something else entirely. This only happens in my Node projects, something I have confirmed by testing numerous Ruby and Apache workspaces.
My Node.js app uses the express, mysql, async, sha1, and socket.io repositories. I have a MySQL server running, though this error also occurs in workspaces in which I do not have MySQL installed.
When node.js app is running in debug mode, cloud9 tries to live update running code using v8 debugger api. This doesn't always work, and when it fails c9 displays this confusing error message.