he said he is right here:Possibly. Unless he's plugging into that outlet that he tried to install a gfci, it is just speculation, and doesn't match the thread.
Yeas....but the generator supplies other circuits in the upstairs house as well. I have a male pigtail that plugs into an interior wall outlet that backfeeds the inside breaker panel. This allows me to energize single circuits as desired an leaving the main feed breaker closed to prevent backfeeding the power pole. If I hooked a switch, I would still need that switch to be connected to a receptacle somewhere outside underneath the house or leave a permanent extension cord wired up to the switch for when the power goes out. Seems like a lot of trouble...
I may simply install a GFI and see if it trips with the harmonics generated by the inverter. I have been using Google and it seems like my chances are not that good though. Here is a sample thread about a guy using a water cooled grinder powered by an inverter that trips a GFI..