I spoke to one of the guys at the PC Gaming Forum. He said that there are no problems with the mouse in IGI but he uses Windows 11 and I have Windows 7 for old games.
Could this be the reason? Winsows 7 is not as supported as it used to be and new programs are less and less working properly.

I doubt this is a Windows 7 compatibility issue with dgVoodoo2. This is more of a "you" issue. There's something weird with the setup on your Windows 7 computer and it is pretty much impossible for us to guess at what that might be.

The only "usual" mouse problems is polling rate issues issues (which isn't the case here, 1000hz works fine at least) and framerate issues (since the game is locked to 60, also isn't the case here). PCGW also suggests this game has problems with mouse acceleration: https://www.pcgamingwiki.com/wiki/Project_I.G … _mouse_movement

If Project IGI is your only concern, it seems to work fine with DDrawCompat:
https://github.com/narzoul/DDrawCompat

You can also probably use Compatibility Administrator (and if you can't, DxWnd surely will work) to make the game run natively in high resolutions, but unless you ask I'm not going to tell you how since I think that just makes the game unplayable because of UI scaling issues:

My computer is a bit outdated (I assembled it in 2015 and only the graphics card was replaced to Geforce 1070 TI) As for my Windows 7 it is 64 Bit installed from the disc but since Microsoft abandoned the support it has not been updated (it only contains Service Pack 1) but it's mainly used for old games, so the latest updates aren't really needed.
Maybe it is a bit of a mess, because the last time I format the disk was over two years ago, but I regularly clean the system with Privazer about once a month.

Since I have a gaming mouse in the mouse settings, the option "Increase the precision of the pointer" is always turned off.
My mouse supports four reporting rates of 125, 250, 500, and 1000Hz, and changing to whatever value doesn't help

As for this DDrawCompat, my game does not start and an error pops up ''IGI.exe has stopped working''.

I also tried to use the old patch for GeForce cards "IGI Loader" but it did not help either.

Today I checked with my friend who has PC with Windows 10 and if I start the game via Dgvoodoo there are no problems with the mouse, so I will wait because next year I plan to update my PC.

I recorded a short video with this problem.
https://www.youtube.com/watch?v=3OLvCu3GQLQ

Try placing a stock dgVoodoo.conf in the game directory if you haven't already, to eliminate any potential configuration file issues. Not that I can think of any dgVoodoo configuration that would cause this issue.

Chris28 wrote on 2022-10-29, 20:23:

Maybe it is a bit of a mess, because the last time I format the disk was over two years ago, but I regularly clean the system with Privazer about once a month.

I would bet on any software that claims to do any sort of system cleaning to create more problems than it fixes. Not that I think it's the cause of this problem.

Chris28 wrote on 2022-10-29, 20:23:

As for this DDrawCompat, my game does not start and an error pops up ''IGI.exe has stopped working''.

Try the build from here:
https://github.com/narzoul/DDrawCompat/issues … ment-1271986474

Chris28 wrote on 2022-10-29, 20:23:

I recorded a short video with this problem.
https://www.youtube.com/watch?v=3OLvCu3GQLQ

Private video, no one can watch it.

Thanks I will try this another build tomorrow. I forgot to make the video public after converting to HD version. Now link should working.