Cannot confirm invalid tile change

[Chad]

Hello

I cannot find an answer to my question anywhere but I am pretty sure it is a problem many others have encountered.

I am new to the game. When I try to build some new room, the construction tiles turn red and I have this error "cannot confirm invalid tile change". I really dont understand what to do because this prevents me from building new rooms and I can't see logically why I have this error....

Can someone explain me how it works?

Thanks !!

[JCH]

sometimes is because is not big enough. It needs a minimum of tiles, usually 4, in a square way preferred. If you put them in arrow, you can have some problems.
Other problem can be if an object blocks the way or leaves a tile unconnected.
If you can share a screenshot would be better

[Edsploit]

Room tiles can't be one-off. They have to be two by two at least. Here's a crappy drawing.

x = placed room tile
Invalid Placements
x

xx

xx
x

xx
x
xx

xx
x
xxx
x

Valid
xx
xx

xxxx
xxxx
xx
xx
xxxx
xxx
xx

[SpellSword0]

It's also possible some tiles somewhere in your base bugged out. This happened to me once where a section of rock my minions filled in had little holes left in it some how. I suggest while in build mode you scan around your base for glowing red spots.

[klemming]

If you click cancel when it gives you the message, it should move the camera to look at the spot it's got a problem with.