In OSX go to System Settings > Share > then look for sharing files with Windows. Heh heh.. That’s great and all. But in my case it didn’t work. “incorrect password” or whatnot. And I kept hitting that wall.
Well, the solution was to “uncheck all the things”, save, then “check all the things”. By that I mean to, say, uncheck/deslect/turn off the OSX accounts that are given permission to be used in SMB file shares from Windows machines. Then save. Then recheck/select/turn on them.. Yeah, it’s really that boneheaded 😉
But the reason is that somewhere under the hood, the configs got clobbered, probably by some system update. So, even though the OS is displaying that the user should work for fileshare, it’s not actually that way.