@Ulf-Gunnel
Yes. That is what I meant. At first, I didn't realize that the base had to be upgraded separately and that the settings were on it, rather than the part that does the moving. So my comment was an attempt to tell you that in case you didn't already know. Since you know that, great. Btw, I found that setting it to run every 6 hours works pretty well for me.
Now, back to the robot not returning to the base. I had that happening with one of the robovacs in the first house that I played in after installing Bust the Dust. It would leave the base, vacuum for a bit and then just stop and sit there. Using the Return to Dock option did nothing. I had put the thing on the floor between two desks next to a floor to ceiling window where it looked like there was enough room and since it placed without MOO on, I thought it was ok but it wouldn't work. The rest of them I put on other floors ran fine with no problems.
Anyway, it took me a few tries to find another spot where it would work. So my suggestion is for you to try putting it in other locations and see if it will return to the dock in another spot. That's what worked for me. I did read here on another post that they are somewhat sensitive and won't work if there are wall mounted objects above them too so I guess, they might not like some windows either. I also put mine a half tile out from the wall as well and stayed away from corners to make sure they had enough room.
The only other time I had when one didn't return to base was when it broke down. But once it was fixed and sent back to the base, it resumed it's automatic schedule just fine.
Hope this helps.
