What causes this error? I have the test extension installed..
I see it from time to time and restarting the browser and TC seemingly fixes it.
Can you confirm that the extension is running in your task manager? if it is not running and you've installed it try a restart of your system.
What version of TestComplete and Browser are you using?
I see it running now but I can't confirm if it was running when I saw this error yesterday, will have to monitor