KF2 Won't Run: 21-Step Fix Checklist and Extra Tips

This is a checklist originally compiled in a pinned fix thread when many players reported the same problems after Killing Floor 2 launched. Try the steps one at a time. For related guides see KF2 will not start (FAQ) and the 0xc000007b fix.

First, if you are not sure about your hardware or software, use a system info tool such as Speccy (its summary page shows everything) or Dxdiag.

The checklist

0. Restart your PC and router.
1. Your PC may be under the minimum requirements. If only Intel graphics limit you, some fixes may help, but the game will probably be buggy: Intel HD 2000/3000 is unsupported. For Intel HD 2500, HD 4000 or newer, update the drivers.
2. Intel HD Graphics plus a dedicated GPU: the game may pick the Intel chip. In the NVIDIA control panel create a custom 3D profile for KF2 (or in AMD CCC) and force the high-performance GPU.
3. The OS must be Windows 7/8/8.1/10 (compatibility mode apparently needed) and 64-bit. Vista was reported to work after step 16.
4. Install, uninstall or reinstall PhysX, even on AMD. It is in steamapps\common\killingfloor2\_CommonRedist.
5. Run Binaries\Win64\KFGame.exe as administrator.
6. Delete the game's folder in Documents\My Games\KillingFloor2.
7. Install the other packages from _CommonRedist.
8. Reinstall GPU drivers.
9. Fixes from the official announcement: verify the Steam cache (Library > KF2 > Properties > Local Files > Verify Integrity), disconnect USB controllers and other HID devices except keyboard and mouse, restart Steam, and launch Steam or the game executable as administrator.
10. MSI Afterburner reportedly stops the game for some people. Close it and any unneeded programs.
11. Turn off the Steam Overlay (Steam > Settings > In-Game).
12. A community-linked tweak (the original links an image).
13. Clean temp files, manually or with CCleaner (untick "only delete files older than 24 hours" in advanced settings, untick browser items on the Applications tab, and run the cleaner).
14. Disable the firewall and antivirus temporarily.
15. A user fixed a crash right after the splash screen by downloading D3DX9_43.dll and placing it in killingfloor2\Binaries\Win64. Only get DLLs from sources you trust.
16. Sometimes the game uses 32-bit DLLs. Replace them with 64-bit versions in Binaries\Win64 (this is the 0xc000007b crash).
17. If the game works in OFFLINE mode only, the likely culprit is your Steam avatar: it needs uniform borders (184x184 max works).
18. Set -dx10 in the launch options (Properties > Set Launch Options).
19. On Windows 8 use Windows 7 compatibility mode (right-click the exe > Properties > Compatibility); on Windows 10 use Windows 8.
20. Install the audio drivers from your motherboard maker's website.
21. If nothing works, post your system summary for help, reinstall the OS or wait for a patch.

Extra tips

• Can't connect to or find servers: set the game language to English.
• The game works but shuts the whole PC down: most likely the power supply, even if other games are fine. Use at least a Tier 3 PSU, and if you already have one you may need more wattage or a better tier.
• No voice acting: it only worked in English at the time, so change the game language.
• Audio problems: try GPU and audio driver updates; see also KF2 audio stuttering fix.
• Stuttering on high-end cards, broken gore, numpad key binding, a screwed-up resolution on NVIDIA and connection loss within a minute of joining all had separate linked fixes in the original thread (images and a Tripwire forum post).
• If you use DxTory, it needs a specific workaround or the game will crash.