import heightmap not working

so all the instructions I've found so far are quite vague on this, but I was able to find my way to the importer for the heightmaps in the new editor, but for some reason I either don't know how it works, or it's just not working.

I can save a preset, and load it. I can select the heightmap png and change all the settings, but when I click "import".... nothing changes.... the button changes colour whilst I click it, but that's about it.

I can create blank terrain blocks, just not with the heightmap that I want. Is it a format thing, or does it need to be an exact resolution?
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ignore this, it had to be a specific resolution (I did attempt this, but made a typo, so I didn't think this was the issue at first)

 

What's the size in pixels of the png you're trying to import? If its in 1:1 aspect ratio did you setup your material to grass?

 

2048x2048 worked
the first one was a 2:1 rectangle (didn't know that wouldn't work) but then I tried to make it square but was accidentally 2040x2048, so I thought the resolution wasn't the issue.
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update, it now crashes when I import my specific heightmaps (I opened other people's mods, and those don't crash). I can usually sit there for a while and nothing crashes, but I can do 1 thing, then it will crash. I can f11 out, move and do everything, but when I f11 back, it crashes. I can also move the camera, but when I stop it crashes, I can click something, but when I stop, it crashes. (as of writing this, it now sometimes crashes before it's fully imported)

I've tried a few things, I was using the raw png from blender, I've saved it from paintshop pro in 24bit and 8 bit, also with colour or grey scale. I even tried jpg, nothing changes it

 

I think a .zip file would be useful

 

hopefully this helps

 

how many mods do you have activated? if it's more than 15 this might be the problem - it happened to me
also maybe clear cache

 

okay, I just deleted a few hundred inactive mods, and now in total (activated or not) 14, and the error still happened
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it now crashes on every heightmap, even after clearing my cache

 

this is still an issue