You may remember me from such adventures as fixing the circle of death. Now it’s fixing error 6. Read on to see how I fixed my roomba with some shiny garbage. 
The Problem:
My current temporary home has carpet that makes my Roomba panic and think it’s falling off a cliff. The Roomba has cliff sensors that are made to stop it falling down the stairs. These cliff sensors are an infrared emitter-receiver pair on the bottom of the roomba. There are 4 pairs.
The sensors regularly send out an IR signal and expect the floor surface to reflect that signal back. If the Roomba is at the edge of a cliff (I e. a stair) there is no light received back and it stops and gives the error message 6. This saves it from certain death or so it thinks. This setup works great unless your floor is too dark to reflect back those IR signals. When that happens the Roomba won’t work at all. Frustrating right?
In my case the dark patches on my carpet are to dark to reflect a signal back.
The Fix:
The fix was to trick the Roomba with shiny reflective foil tape. Shiny tape over the cliff sensors easily reflect back the IR and keeps the Roomba happy and sailing along no matter what colour carpet it is cleaning. Now if only we could all stick shiny tape over our eyes life would be good. 
I had zero foil tape on hand but I did have the adhesive flap cut off an old insulated double-sided foil bubble wrap envelope. I cut it up, stuck the adhesive side on the sensors, and my Roomba is happy again. This will work as a temporary fix.
This fix took 5 minutes and now I don’t have to vacuum my place by hand. Hooray!