I just wanted to post my solution to this error that was preventing me from saving in Substance 3D Painter 7.4.3. I had seen several posts saying this is caused by having lost/unallocated textures in the file, but I did not have any. What solved the issue was deleting the default "Layer 1" paint layers that Painter automatically adds to each texture set. I imagine any empty layer could cause this error. It seems incredibly neglectfull that the file defualts that ship with a software are completely preventing user files to be saved in some cases.
Filing a bug report for this as well, but figured it would be useful as a topic here in the meantime.
It didn't work for me deleting the layers created by default by substance but I opened the error log and right clicked + clear and it let me save. It also makes a lot of sense...
it didnt make sense to me when you just have to clear the error log but it works for me man. Thank you !
I was just having this issue. Mine was caused by an imported texture. Not sure why there was a problem at all, as I've done this many times before, but I created an ID map outside of substance and imported it to my project. All my other maps were baked in Substance. Once I removed the file from my project completely (cleared from baked maps and cleaned my file), I was able to save again. I tried reimporting the file again to see if it would work, but had the same issue. So, ended up unable to use my id map.
Na nothing is working..there's no default layers, cleared extra resources, still giving error [ResourceImage] Can't serialize empty surface