Try to delete textures have weird name. (Watercolor Simple, Dry Watercolor, etc...)
I delete some textures from Trev's brushset, imported and it worked.
EulerStalker, thanks again for the swift reply. Here's what I've done:
1. I'd like to import the missing brushes (i.e. Watercolor Simple, Sumie, etc) from version 1.2.7 into version 1.3.1.
2. I don't have these individual brushes, so as you suggested I took ver. 1.2.7's Tools folder and swapped it with 1.3.1's Tools folder.
3. The old brushes are there now, but none of 1.3.1's new brushes or settings are there anymore.
4. I decided to try to export the brushes so I could save to my computer, then drag BACK into Clip Studio 1.3.1 after I put back 1.3.1's Tools folder. That way I'd have all the new brushes/settings for 1.3.1 AND the missing brushes from 1.2.7. I clicked Export Sub Tool for each missing brush (i.e. Watercolor Simple, Sumie, etc) , but...
5. I get an error message when I try to export saying "Failed to write the sub-tool", so it won't let me export the brushes I want.
I took your suggestion and clicked on each brush I was missing (i.e. Watercolor Simple, Sumie, etc) then clicked on Texture, deleted the texture, then tried to export the brush again, but I'm still getting the same error message. Any ideas why I can't export these brushes? Is there a way I can find the individual brushes themselves?
Thanks for any suggestions!