Rainbow Six Siege Anti-Cheat Error Fix (Error 50, BattlEye)

A Rainbow Six Siege anti-cheat error almost always means the anti-cheat’s own Windows service or driver failed to start, not that your account is flagged. Siege now runs two anti-cheats on PC, so match your message first: “Failed to start the driver service (error 50)” and other numbered driver-service errors come from Ubisoft Anti-Cheat — repair it from the game’s Sentinel folder (jump to that fix). “Failed to start BattlEye Service” comes from BattlEye — work through Fixes 1–6 below. Both are local problems that rarely need a full reinstall.

Ubisoft Anti-Cheat: “Failed to start the driver service”

In August 2026 Ubisoft announced that Siege would be one of the first games to adopt its new kernel-level anti-cheat, shared across Ubisoft games, with players notified when they launch the game in Year 11 Season 3. Its errors look different from BattlEye’s: a launcher message such as “Error: Failed to start the driver service (error 50)”, “Failed to start the Ubisoft Anti-Cheat service (error 1392)”, or “Ubisoft Anti-Cheat failed to launch game”.

What the number in brackets means

The number is a standard Windows system error code — it tells you why Windows refused to start the anti-cheat driver. Microsoft’s definitions:

Code in the message	Windows name	Microsoft’s meaning	What to try first
50	ERROR_NOT_SUPPORTED	”The request is not supported.”	Repair Ubisoft Anti-Cheat, then install Windows updates
1392	ERROR_FILE_CORRUPT	”The file or directory is corrupted and unreadable.”	Verify game files, then Repair; if it repeats, check the drive
1450	ERROR_NO_SYSTEM_RESOURCES	”Insufficient system resources exist to complete the requested service.”	Restart the PC, then launch with nothing else open
1061	ERROR_SERVICE_CANNOT_ACCEPT_CTRL	”The service cannot accept control messages at this time.”	Restart the PC so the stuck driver service clears
740	ERROR_ELEVATION_REQUIRED	”The requested operation requires elevation.”	Run the launcher as administrator
5	ERROR_ACCESS_DENIED	”Access is denied.”	Security-software exclusion + run as administrator
577	ERROR_INVALID_IMAGE_HASH	”Windows cannot verify the digital signature for this file.”	Install all Windows updates, then Repair
0xe6650003	—	Not a Windows system error code; Ubisoft hasn’t published its meaning	Follow Ubisoft’s three steps below

“Insufficient system resources” also shows up in the BattlEye launcher — it’s the same Windows error 1450 underneath.

Ubisoft’s fix, in order

Ubisoft’s own Ubisoft Anti-Cheat troubleshooting article (updated September 2026) gives three steps — test the game after each one:

1. Verify your game files in Ubisoft Connect, Steam or the Epic Games Launcher.
2. Repair Ubisoft Anti-Cheat. Open the game’s installation folder, go into the Sentinel folder, right-click UbisoftAntiCheatInstaller.exe, choose Run as administrator and pick Repair. If that doesn’t help, run it again and pick Install to reinstall. (Ubisoft Connect’s default games folder is C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\games; on Steam or Epic, open Siege’s folder in that library.)
3. Check compatibility. Make sure no security software blocks Ubisoft Anti-Cheat, and add the Ubisoft Anti-Cheat .exe to the exclusions list in Windows Security.

If the error survives all three, Ubisoft asks players to report it through its bug reporter. Ubisoft Anti-Cheat installs and uninstalls itself with the game, so there’s nothing to remove by hand.

”My PC restarts when Siege installs the anti-cheat”

Searches like “PC restarts when installing BattlEye for Siege” describe a whole-system crash during the anti-cheat install, not a launcher error. Loading a kernel driver is where an unstable overclock or a conflicting low-level tool tends to surface. Run the Repair step above, revert any CPU/GPU/RAM overclock (including XMP/EXPO) for one test launch, and if Windows shows a blue screen, note the stop code before reporting it to Ubisoft with the launcher’s error text.

BattlEye: what the error usually looks like

• “Failed to start BattlEye Service” on launch, right before the game would normally load
• The BattlEye launcher window hangs, then closes the game
• Siege closes immediately after the Ubisoft Connect splash screen
• The error reappears even after a normal Steam/Ubisoft Connect restart

All of these point to the same root cause: BEService.exe, the Windows service BattlEye installs and runs, isn’t starting cleanly.

Fix 1: Reinstall BattlEye manually

This is the single most effective fix and solves most “Failed to start BattlEye Service” errors on its own.

1. Go to your Siege install folder (e.g. ...\Tom Clancy's Rainbow Six Siege\BattlEye).
2. Right-click Install_BattlEye.bat and choose Run as administrator.
3. Let it finish, then relaunch the game.
4. If the folder is missing or won’t run, verify game files first (Fix 2), then retry.
5. Still failing? BattlEye’s FAQ (republished by Ubisoft) says to delete the BE Service folder — usually C:\Program Files (x86)\Common Files\BattlEye — and launch again, which fixes permission problems in that folder.

Fix 2: Verify game files

1. In Steam: right-click Rainbow Six Siege → Properties → Local Files → Verify Integrity of Game Files.
2. On Ubisoft Connect: open the game’s settings and choose Verify Files.
3. Let the check finish completely before relaunching — don’t interrupt it.

Fix 3: Run everything as administrator

1. Right-click your launcher (Ubisoft Connect, Steam, or Epic) and choose Run as administrator.
2. Right-click the Siege executable itself and enable Run this program as an administrator under the Compatibility tab.
3. Relaunch and check whether the service starts.

BattlEye needs to install and run a Windows service; restricted permissions are a frequent, silent cause of the failure.

Fix 4: Check antivirus and firewall

1. Open your antivirus and add exceptions for the Siege install folder and the BattlEye folder inside it.
2. Confirm BEService.exe and BEDaisy.sys aren’t quarantined — restore them if they are.
3. In Windows Firewall, allow Rainbow Six Siege, your launcher, and BattlEye through both private and public networks.
4. Temporarily disable third-party antivirus (not just Windows Defender) to confirm it’s the cause before deciding on a permanent exception.

Fix 5: Check the BattlEye Windows service directly

1. Press Win + R, type services.msc, press Enter.
2. Find BattlEye Service.
3. Set Startup type to Automatic and click Start if it isn’t running.
4. Restart your PC and relaunch Siege.

Fix 6: Update Windows and your GPU driver

1. Install all pending Windows Updates — BattlEye depends on current system files and won’t reliably start on an outdated or non-official Windows build.
2. Update your GPU driver to the latest stable version.
3. Restart before testing again.

When to do a clean reinstall

If none of the above works, uninstall Siege completely, delete any leftover install folder, and do a fresh install. This clears out any deeper corruption in the BattlEye files that a simple repair can’t reach — but treat it as a last resort, since the manual BattlEye reinstall in Fix 1 resolves nearly all cases first.

Related guides

• Rainbow Six Siege Stuttering Fix: Stop FPS Drops and Hitching
• Rainbow Six Siege Stretched Resolution Guide
• Best Rainbow Six Siege Settings for FPS and Visibility
• 10 Ways to Run Command Prompt as Administrator
• EAC vs BattlEye vs Vanguard vs Ricochet vs VAC compared

Most Rainbow Six Siege anti-cheat errors come down to a broken service install, blocked antivirus, or missing admin permissions. For Ubisoft Anti-Cheat driver-service errors, repair it from the Sentinel folder; for BattlEye errors, reinstall BattlEye manually first, verify your files, and check antivirus and firewall exceptions — that combination clears the error for the large majority of players without a full game reinstall.