1.Client errors are unpatchable without hacking the crossfire servers. So please don't ask to fix them!
2.Some hacks will cause instant client errors and can not be used anymore.
3.Other hacks will only cause client errors if you use them too often (abuse).


The following (incomplete) list shows you the error codes and what functions may cause them:

1.
Code:
•Error code: 1_0, 1_2
•Caused by: Speed Hack
•Notes: Speed Hack works without any error up to 120% - 125% of the normal speed.

2.
Code:
•Error code: 11_0, 11_1
•Caused by: C4 plant & defuse Hack

3.
Code:
•Error code: 13_0
•Caused by: Knife Range Hack
•Notes: Causes error after 1 kill however you can make it undetected. //Credits - Abel09

4.
Code:
•Error code: 14_0, 14_1, 14_2
•Caused by: Attack Speed Hack, Fast Reload
•Notes: Don't abuse the fast reload hack. Careful usage works without an error.

5.
Code:
•Error code: 18_0
•Caused by: Shoot through wall Hack
•Notes: Works fine for the NA version, but causes client error in Crossfire EU.

6.
Code:
•Error code: 19_0
•Caused by: Animation Hack, Master Ghost

7.
Code:
•Error code: 20_0
•Caused by: Escape Hack

8.
Code:
•Error code: 21_0
•Caused by: Flash bang Hack

9.
Code:
•Error code: 22_0, 22_1, 22_2, 22_3
•Caused by: Damage Hack
•Notes: Damage Hack works fine with a value of ~120% for the most weapons.

10.
Code:
•Error code: 24_0, 24_1, 24_2, 24_3, 24_4, 24_5, 24_6, 24_7, 24_8
•Caused by: Player position & movement Hack, Teleport Hack, Super Jump, Fly Hack, Glitching

11.
Code:
•Error code: 25_0
•Caused by: Grenade Type Hack

12.
Code:
•Error code: 28_0, 28_1, 28_2
•Caused by: Hidden/Invisible Hack

13.
Code:
•Error code: 22_1
•Caused by: Sniper Weapon Hack

14.
Code:
•Error code: 31_0
•Caused by: Rifle Weapon Hack