As zzsim said, maybe the NAM is the problem, for me, I am sure that the crashes cause the NAM must have tool. Yes, I said must have because I can't play without it. Without it the game runs normal i have one map with 500K sims, but with NAM i have crash problems. I will keep using the NAM because I LEARNED to "not get mad by CTD"
I have only crashes when I zoom out, subway tubing (undergroud CTD) and GLR placeing. Rarely I have save problem, BUT, from this I can recover.
My computer: P4HT-2,8/1GB-RAM/MSI Neo2/MSI 6600GTS/Win2000 orig.
ALL my saving problem is that it still saves and the only thibnk to stop this is to make CTRL-ALT-DEL.....and cancel the application. BUT, after quiting to manager I give it a few time to sort processes and than i click back on simcity as i would like to pop it up back, after few blinking screens of region (yes, i dont why there are region map while i am going back to game from manager) the game get back and voila, save was succesfull tab appear. This was my last saving crash....CAUTION, this procedure takes me about 5 minutes, but i don't lose my save!
Another crashes are the ones mentioned here by Barbyw and others, and my solution to "not get mad by CTD" is patience, not so much quick zooming, scrolling and so one.
I have region of 5MIO sims, 20cities, 3GB Plugin folder....
Also, when I SUFFER from a crash i restart my PC and my simcity keeps runing for 2-3 hours without crash. Than i reboot again and again.....
You know, my bugfight is in patience and I must say that i'm winning because a have: "More beer cans in trash, than simcity crash" and this is fine, not perfect, but it works.
