I’m using Sudoku 10'000 Free 2.42. I found this problem when I create an empty Sudoku and then edit it.
When I enter a Sudoku from the local newspaper & make a mistake in a cell & erase it to a blank (the wrong cell), then finish entering the givens, and then save it, I get a “Invalid Sudoku†when I ropen it to play it and analyze it. If I erase that invalid Sudoku & reenter all the same givens without making a mistake, I get a valid Sudoku. Ron