Easy Anti-Cheat verifies that the game client and Windows itself have not been tampered with. When something does not match it stops the launch — and the wording almost always identifies what. Here are the messages, one at a time.
The anti-cheat runs a kernel-level driver: it verifies game file signatures, the integrity of Windows system libraries, whether anything is injected into the process, and whether a debugger is attached. Two consequences follow. First, most EAC errors are not a broken game but a refusal to trust your system. Second, "lite" Windows builds, manually swapped DLLs and disabled driver signature enforcement break it reliably.
The service is missing or was quarantined by antivirus. Fix it with the installer shipped inside the game folder:
EasyAntiCheat and run EasyAntiCheat_Setup.exe as administrator.If the installer itself errors out, check your antivirus quarantine. Defender and especially third-party suites regularly flag the anti-cheat driver.
The message names a file — a Windows system library whose signature did not match. Causes: an "optimized" Windows build, a DLL replaced by hand on someone’s advice, an interrupted update, occasionally disk corruption.
sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannowThe second sfc is not a typo: DISM repairs the reference store, and only then does the rescan have correct copies to pull from.
chkdsk C: /scan.The anti-cheat found a program next to the game that injects into processes. Injection is indistinguishable from cheating from its point of view, however harmless the program is.
| Program | What to do |
|---|---|
| MSI Afterburner / RivaTuner (RTSS) | Close before playing, or disable the overlay |
| Discord | Disable in-game overlay in settings |
| GeForce Experience / NVIDIA App | Disable the in-game overlay |
| OBS with Game Capture | Switch to Window or Display Capture |
| Razer Synapse, iCUE, Nahimic | Close, or update to the latest version |
| Controller emulators, macro software | Close entirely |
| VMs, Sandbox, debuggers | Disable, including Hyper-V |
Diagnosis is simple: close everything non-essential in Task Manager and launch. If it works, re-enable programs one at a time until it breaks again.
A separate family of causes: the anti-cheat expects Windows to boot normally rather than with its own checks disabled.
bcdedit /enum {current}
Confirm-SecureBootUEFI
Get-Tpm | Select-Object TpmPresent, TpmReadybcdedit shows testsigning Yes, turn it off: bcdedit /set testsigning off, then reboot.nointegritychecks: bcdedit /set nointegritychecks off.EasyAntiCheat folder from the game directory and verify again — Steam re-downloads it.%LOCALAPPDATA%\Facepunch\Rust (back up client.cfg first).And a blunt note: if Windows is a third-party "gaming" build with components removed, EAC errors will keep coming back. It checks the whole system, and what was stripped out cannot be repaired.
Worth stating because people ask: Windows settings, registry values, driver panel options and client.cfg are not what the anti-cheat inspects — it looks at the game process and system file integrity. The risk comes from software that injects into the process or installs its own kernel driver, not from tweaks. There is a separate article on exactly where that line falls.
Yes, it is one of the most common causes. Antivirus products regularly quarantine the anti-cheat driver as suspicious. Check the quarantine, add the game folder and EasyAntiCheat.exe to exclusions, then run Repair Service.
Rust itself does not. But the anti-cheat refuses to run if Windows is booted in test-signing mode or with driver integrity checks disabled. Check bcdedit: testsigning and nointegritychecks should both read No.
Usually after a Windows update, a new driver, or installing something with an overlay. Think about what changed in the last few days and start there. An interrupted Windows update also produces untrusted system file.
Rarely, because the cause is usually outside the game — system files, antivirus, or another program. Start with the anti-cheat Repair Service and verifying game files: faster, and it fixes most cases.