How to solve the client crash issue?

Please try to download the client from http://co.99.com/downloads/ and reinstall it again for a try.
And you can download the patches from http://co.99.com/downloads/patch.shtml and save them to the conquer folder to reinstall.
Please also check if your firewall or antivirus blocked Conquer Online.
If the above doesn't work, please send us the latest debug files to co@netdragon.com and we'll forward the issue to our technical team for further check.