Feral Heart

You may want to consider flattening your image as well. This can be done by right clicking on your single layer and selecting "Flatten Image"

aAAAAAA THANK YOU! i'm mildly mortified that i missed that as a solution //sheepish grin// there was probably a tiny spot of transparency at the edge that was screwing me over, considering i had used a smudge tool near the edges and i forgot that it tends to drag the color off of the area and reveal transparent edges. ah, well. thank you a ton!

alright, so, i've actually never had this problem on my old laptop and this is... not fun. decidedly not fun.

my map is
-513x513
-greyscale
-one layer
-.png file
-lowercase name Uppercase Terrain no spaces, numbers, or symbols
-alpha channel was never used and therefore never not on

solutions i've tried:
-i've tested the brushes used in it on my testdummy map, which works perfectly (which is scream-inducing enough because seriously only the tESTDUMMY MAP WORKS?)
-i've copied and pasted the heightmap to another canvas, greyscale, 513x513, .png, even changed the name, and it refused to work
-triple-double-checked that everything is in order
-ran as admin, in case that worked, but nope

also, it's not just that map. the other map i made after i realized "okay maybe this wont work" doesn't work as well.

thanks for reading! hopefully someone has a solution?
have a lovely day/night! be safe!
-ember

edit:
okay so i got it working, thank you so so much! i worked for a good 3 hours on this map and i'm extremely happy i can use it because honestly it's one of my favorites! i just had to freaking flatten it, there was probably a bloody patch of transparency i missed x-x regardless, thanks again!