Whenever my opponent quits instead of resign; my game crashes and either I lose points or the game is marked as non-rated due to the crash. Players are now using this trick against me whenever they are losing. How do I solve this issue?

Could you please run the game diagnostic tool from the lobby menu and paste us the results here? Thanks.

https://www.voobly.com/match/view/26849722 this is an example of a game

Yes, Here's the log

Non-DirectPlay game path is 'C:\Program Files (x86)\Microsoft Games\Age of Empires II'
Verifying 'C:\Program Files (x86)\Microsoft Games\Age of Empires II\language_x1.dll' exists...
Success!
Verifying 'C:\Program Files (x86)\Microsoft Games\Age of Empires II\age2_x1\age2_x1.exe' exists...
Success!
Voobly path is 'c:\program files (x86)\voobly'
Game version is '1.0C-VLY'
Verifying 'C:\Program Files (x86)\Microsoft Games\Age of Empires II\language_x1_p1.dll' exists...
Success!
Checking DirectPlay libraries...
Looking for dpwsockx.dll...
Looking for dplayx.dll...
'c:\windows\system32\dplayx.dll' size: 215552 bytes
DirectPlay Init Success!
Scanning installed DirectPlay games...
Age of Empires II
Age of Empires II - The Conquerors Expansion [found]
Game was found in DirectPlay registry!
DirectPlay play thinks the game is installed at 'C:\Program Files (x86)\Microsoft Games\Age of Empires II'
DirectPlay command line is 'lobby'
DirectPlay play thinks the game exe is at 'C:\Program Files (x86)\Microsoft Games\Age of Empires II\Age2_X1\age2_x1.exe'
Verifying file exists... Success!
DirectPlay play thinks the language dll is at 'C:\Program Files (x86)\Microsoft Games\Age of Empires II\language_x1.dll'
Verifying file exists... Success!
Scanning 'c:\program files (x86)\voobly\gamedata\AOC\age2_x1.exe'
Success!

Everything looks fine. DirectPlay is configured and the game was found on your harddrive. If you still have problems try rejoining the lobby or restarting your computer.

and this keeps happening
https://www.voobly.com/match/view/26874366

Is it possible, that the crashes are related to the No Walls mod? Please test and see, whether you have the same problem, without the mod.

No GA DMer is willing to play without that mod so hard to test when the opponent doesn't perform the action in Michi DM

Could you please disable any other visual mod to ensure, it's not the combination of several mods that is causing the problem?

I did disable visual mods and still doesn't help. The only ones I kept enabled are HD Hotkeys & TheViper Hotkeys

Keeps happening. I hate players taking advantage like this. No fun playing to always lose even when I won.
https://www.voobly.com/match/view/26911249

Please perform a clean installation of the game. This should resolve the crashing issues:
[You must login to view link]