As per the title at random intervals during play the mouse can get stuck to one side of the screen. It was the left at first, but just recently it got stuck to the top. This means I can't even save my progress before quitting and windowing / maximising it doesn't help, although the mouse pointer is as normal outside the windowed screen, it's still stuck in the game.

Running this on Win10 which might be part of the problem I don't know.

Happened to me in 1st person because I kept spinning to the left, so i figured it out. Had to unspin, a lot. Mouse can only be moved so far in one direction (left, right, top, bottom) before it gets stuck there and it need to be moved the other direction

This is a common problem, but I think that it might still be possible to save with ALT+R ?
https://www.gog.com/forum/dungeon_keeper_series/dungeon_keeper_1_the_mouse_keeps_moving_to_the_left/post9

It's definitely not a win 10 issue. I've had it happen several times in win7. It's more of a bullfrog issue I think. One of their other games did it as well. Theme Hospital I think. It's definitely annoying when it happens but thankfully for me it was pretty rare. I just made sure I saved slightly more frequently than usual as a precaution.

It already is in high res mode. But maybe that will work just as well. I'll give it a go the next time it happens. So if it's stuck on the left side moving right a lot will free it? Worth a try, but I guess it's best to just save and quit if that works.

It doesn't require restarting. It happens when there's a bias in the direction the mouse is moved, eventually it hits an imaginary edge. Just move it a ways in the opposite direction. That's the fix.

that doesnt help... ive had to close the program down and restart it. ive just resulted to saving my games every 10mins to avoid having to restart the level.
ive tried moving it in all directions but that doesnt work (might for you but not for everyone)

I've contacted support about this and they recommended KeeperFX. The good news is that it fixes the problem (as well as giving you much better resolution options) but the bad news is that for me at least it completely broke the game's AI. I'm going to have to play around with this thing a bit and see if I can't get it working like it's apparently supposed to. But I thought it might help others with this issue in the meantime.

I encountered the same problem, and I managed to get the game saved at least, using the same method described here.
If you are in high res mode, press Alt+R to get to low res, then press Alt+R again to get to high res mode again. Now your mouse is still stuck, but in the middle of the screen. Coincidentally, just where the save button is. So press escape, save your game, and then restart; at least you don't lose your progress.

Moving it in a little circle won't help. Try moving it a lot more, and only in the correct direction, the one opposite to the way your mouse was moving when it stuck. Yeah this was exactly what was happening to me. For what it's worth, your score gets confused by reloading save games, but I did the save and restart method before I figured out it wasn't necessary.

This bug was in the original game (97)^^ but at that time I fixed the bug with open and close my cd-rom.^^

Yeah I hate this bug and I don`t understand why they sell the game furthermore. I can´t play the game because I can`t save . (Yes I tried many things)

It is often caused when you've used alt+tab before. The game resolution is much smaller then your regular resolution and it happens when your mouse gets too far to one side. As mentioned above moving it in the opposite direction a lot should work, but if not you could also minimize the game, move the mouse, and go back to the game again.

Also, if you want to prevent it, don't switch between this game and doing something else. If you want to, simply save and close the game.