I had the same issue with my GE GDF570SSF4SS... suddenly the dishwasher stopped draining all the water after the last cycle. I disassembled and cleaned everything possible... no luck. Replaced pump drain and wash pump... no luck. Replaced flood switch... no luck. After reading many forums and different people with the similar issues, I kept coming back to there must be a clog somewhere, but always wondering how... if I could see the water going out and hear the pump working...it just didn't make much sense. So, I took the machine out one last time and completely removed the drain hose out for sanity sake (since I had already snaked it from the disposal side and did not find any debris). I took it outside and tried to flush it as much as possible with the water hose...water was flowing, but didn't seem as much as it should be, so I kept doing it for a while. Afterwards, I shook the valve side (L shaped) on my hand and suddenly a small round furniture bumper sticky (those round things we glue to inside cabinet doors and drawers) came out of the valve. Flushed water through again and voila... full pressure it seemed. I put everything back together and ran a quick test... NO WATER left. I still don't know how that bumper sticky got in there since it is not the same as the ones we have in our kitchen furniture...maybe it got stuck on a dish somehow or was lodged in there all this time since the house was built and now decided to get into the wrong place... anyways, it doesn't matter now... the problem is resolved. So, as many others have advised, check the following first:
1-all filters
2-drain hose (take it out completely and flush it well or replace it). Depending on the model, the hose will have the valve the prevents water from coming back into the machine and that was the case for me. If yours is different, find the valve and clean or replace it.
3-food disposal
4-pump
5-flood switch
I am not a professional by any means... just sharing what finally worked for me. Hope it helps anyone out there. Good luck.