When playing long custom games the game randomly crashes with a memory error crash report. It usually appears very fast and then dissapears.

Anyone having the same problem?

Try increasing DOS high memory size by editing DOSBox config file.

Browse to the game directory and locate DOSBox config file (dosboxConquest_single.conf or similar name), then open it with a text editor. Under the [dosbox] section edit (or add if not already present) the memsize settings: memsize=32 or memsize=64 (default value is 16). Then save the file and launch the game.

Sorry for a late reply but does that really help for you?

Honestly speaking, I haven't tried this myself: it's a general advice when a DOS game crashes reporting a memory error.

I am not very sure increasing DOSBox memory over 16 MiB does really help...
https://www.dosbox.com/wiki/Dosbox.conf - however manual does not mention this as an issue... maybe worth trying anyway.

I do have the same issue from time to time... even early in the game.
(I do not use GOG DOSBox, I have my own install)
Maybe it is worth trying other flavors of dosbox? like this: https://dosbox-staging.github.io

And one more point, I am pretty sure when I was originally playing this game on some Intel Pentium hardware
it was crashing from time to time as well. It might be just unfixable bug.

and to stop the error message from disappearing just remove exit command from your shortcut and your dosbox.conf

Let us know if any of that stuff helped you. :)

Hope it is not a game bug but a dosbox one. I will try it thank you!