EAC: "Modified Windows bootloader detected"
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Symptom
Section titled “Symptom”A game protected by the EasyAntiCheat (EAC) anti-cheat does not start: the anti-cheat shows an error such as “Modified Windows bootloader detected” and closes. Before that, Windows had usually been “optimized” with tweaks.
Typical causes
Section titled “Typical causes”- Tweaks that disable Windows kernel protection (Kernel Patch Protection, “patch guard”) have been applied. EAC requires the standard kernel protection and refuses to launch the game while it is disabled.
- Some “optimizer” tweak collections disable kernel protection on purpose. If any of those were applied, the problem is not in the game or in EAC, but in the modified system.
Fix in BoosterX
Section titled “Fix in BoosterX”Open BoosterX → “Fixes” (in the left menu) → in the search field enter “EAC Kernel Patch Protection disabled” → “Fix” → restart Windows. The fix re-enables Windows kernel protection, which the EAC anti-cheat requires.
BoosterX can be downloaded from the official website boosterx.org.
How to verify
Section titled “How to verify”Launch the game with the EAC anti-cheat: it should reach launch without the bootloader message.
Manual alternative without BoosterX
Section titled “Manual alternative without BoosterX”Restore the kernel protection settings to their defaults: Settings → Windows Security → Device security → “Core isolation details” — enable “Memory integrity” and restart the computer. After mass tweaks, also check the remaining items in the Security settings section: anything disabled by policies may interfere with protection.
If it did not help
Section titled “If it did not help”Verify the integrity of the game files in its launcher, collect the event log via EventX and, if necessary, contact support.
Last checked: 2026-09-20. Full catalog of fixes.