Technical issues in Heroes IV.

Hey everyone, I have a question. I updated Windows to 10. Yesterday, I was playing Heroes of Might and Magic IV and encountered an issue where the autosave feature isn't working. After each turn, I get a message saying "Failed to autosave." The game is a licensed version, as is Windows. Has anyone else encountered this problem and found a solution?

I'm having the same problem. The autosave feature isn't working in the game. + During battles: lag and slowdowns. The animation of certain things takes longer than it should, especially when arrows are flying, etc.
Before this, I had other lag issues (a black screen at the beginning), but I solved them. However, I haven't been able to solve the problems described above. What do you suggest?
* Various settings and compatibility mode tweaks didn't help with the lag and slowdowns during combat.