I am having the same exact problem as well with the Flophouse quest. Because of this I cannot establish the colony, which means I can't complete many of my outstanding quests. I have tried all of the solutions to this bug that others have tried, and none of them work.
This is on a PS4 Pro, with version 1.04.
OK so I finally was able to finish the quest. Here are the steps I took, hope this helps others.
I left the planet, and came back. Went to the flophouse and started engaging all the scavengers. Worked my way all the way to the top to the far east building (You can turn off the alarms if you want). There is no marker for this on your map, once you approach the correct building SAM will talk about hacking the security. Inside the building there are 2 terminals, one of them you "hack" which starts a wave of enemies. Once complete the bottom building is unlocked and you can proceed with finishing the quest. As soon as the quest completed I got an updated quest to build the outpost. I believe the bug is that you can complete the Remnant core quest before engaging this side of the flophouse, which is what I did. That door should be locked until this is completed to prevent this from happening.
I followed this to make sure I was not missing anything. Hopefully this helps other out with this bug.
http://masseffectandromeda.wiki.fextralife.com/The+Flophouse
Very frustration EA, I spent 4 hours trying to figure this out with 100% viability on Elaaden. Please fix this quest.
My fix for all quest bugs(so far) has been to walk about 100m away,save game,exit game.Re-load game hit Resume,go back to problem area and its fixed.
This has worked every time for me
81% viability I do not know if is same issue, but I know I have the settlement Icon on the planet, and I can not activate it. I have walked all around it, and approached it from every direction, but it will not bring up the click thing, and let me activate it.
I have the same thing on Kaldara, 74% viability, and no matter what I do the settlement will not allow me to click on it. I have cleared the cave with the Kett in it. where Sloan shows up to supposedly help.
My Hours playing are racking up because of this,but they are not actual playing hours, just wandering around Hours, trying to figure out why the game will not advance... it is troublesome.. to the maddening rage state.
You need to clear the flophouse in order to establish the outpost. as long as the flophouse is not cleared you just can't proceed making an outpost no matter how high your viability score is. I guess you can't see the flophouse quest icon on your map and assumed you cleared it. My suggestion is to go back to the flophouse location and see if there are still enemies. If there are proceed to kill them and go to the house where you have to hold out until a hack is completed. Then go the building you couldn't enter previously. Clear out both the first and second floor and activate the switch at the end. The "Flophouse" side mission should be cleared now and you'll be able to put down the outpost. Hope it helps!
I had the same issue, left the planet came back, saved quit, then went back to the location, took a little bit to get the terminals worked out, for me they kept showing up as markers then, I would do one they would blink out, kept scanning & eventually it worked out. Was a pain though, like others I stumbled across it driving, the original hack just glitched out. Hope it helps.
Cheers
Confirmed. Leaving planet coming back and FULL clearing (to find where you messed up) and SAM will set you straight.
