VAN 148: Vanguard tripped while starting or checking your PC

Vanguard Error: VAN 148. An unexpected error with Vanguard has occurred and the client will now close.

Permissions come early on this one

Riot's second fix for VAN 148 is running the Riot Client as administrator, and the reason it gives is Windows permissions getting between the client, the game and Vanguard. It's quick to test (one right-click) and it comes before the service change and every reinstall, so do it in that order. If it works, the shortcut's Compatibility tab can make it permanent.

Only one other VAN article has that step: VAN 1067. The two lists are close cousins. Take the malware scan out of VAN 1067's and you get VAN 148's, in the same order.

Two steps Riot moved around

Compared with most VAN lists, VAN 148 runs a clean boot before the Vanguard reinstall, and puts the connection checklist ahead of reinstalling the game. The game reinstall is the heaviest job on the list and Riot leaves it for last. Follow this order here even if another VAN page gave you a different one.

The wording on screen is the "Vanguard Error ... the client will now close" line, the same one VAN 57 and VAN 2266 use. It doesn't mean the same thing as either of them, and their fixes differ, so go by the number.

Riot's fix, in Riot's order

1. Install every pending Windows update

   Open Settings, then Windows Update, and keep installing and restarting until it says you're up to date. Vanguard's checks lean on security components that ship in those updates, and optional driver updates are worth a look while you're there.

2. Run the Riot Client as administrator

   Right-click the Riot Client shortcut and choose Run as administrator, then launch from there. If that fixes it, you can make it stick from the shortcut's Compatibility tab.

   Riot's guide: Run the Riot Client as administrator

3. Set the vgc service to Automatic

   Vanguard has two parts: a driver that loads at boot and a Windows service called vgc. If the service isn't running when you press Play, the game closes.

   1. Press Win+R, type services.msc and press Enter.
   2. Find vgc in the list and double-click it.
   3. Set Startup type to Automatic. If the status says Stopped, click Start.
   4. Apply, OK, then restart the PC.

   The exception is Vanguard Pre-Check, Riot's opt-in mode where Vanguard only runs while a game is open. It needs Windows 11 25H2 or newer plus Secure Boot, TPM 2.0, IOMMU, VBS and HVCI, and if you're on it you shouldn't force the service to Automatic.

   Riot's guide: Set the vgc service to Automatic

4. Do a clean boot

   This switches off every non-Microsoft service for one boot, so you can tell whether something in the background is the problem.

   1. Press Win+R, type msconfig and press Enter.
   2. On the Services tab, tick Hide all Microsoft services first (skip it and you'll switch off parts of Windows).
   3. Click Disable all, then tick vgc again so Vanguard still starts.
   4. Apply, OK, restart, and test.

   Some programs ignore a clean boot anyway, third-party antivirus and networking tools most of all. If the error goes away, turn services back on a few at a time until it returns, and you've found it.

   Riot's guide: Do a clean boot

5. Uninstall Vanguard, restart, and let the game reinstall it

   1. Close the game and exit the Riot Client from the system tray.
   2. Right-click the red Vanguard icon in the tray, choose Advanced, then Uninstall Vanguard. If the icon isn't there, search Windows for Add or remove programs and uninstall Riot Vanguard from the list.
   3. Restart the PC. Vanguard is gone if its tray icon doesn't come back.
   4. Open the Riot Client and launch the game. It reinstalls Vanguard and will ask for one more restart before Play unlocks.

   Riot's guide: Uninstall Vanguard, restart, and let the game reinstall it

6. Work through Riot's connection checklist

   Last on Riot's list for a reason: only get here once the Vanguard steps above have failed. Riot's PC connection guide covers the usual suspects: a wired connection instead of Wi-Fi, restarting the router, switching to a public DNS, firewall exceptions for the Riot Client and game, and turning off VPNs.

   Riot's guide: Work through Riot's connection checklist

7. Reinstall the game

   Uninstall from Windows' Installed apps list with the Riot Client closed. For a clean reinstall of League, Riot also has you delete the Riot Client folder under C:\Riot Games, the Riot Games folders under %localappdata% and %programdata%, and the League of Legends folder in Documents. That last one holds your replays, so copy them out first if you want them.

   Riot's guide: Reinstall the game

Related errors

• VAN 1067
• VAN 140
• VAN 2266
• VAN 57

Source: Riot Games Player Support, Error VAN 148, updated July 15, 2026. Riot's steps are paraphrased here, not copied; checked September 25, 2026.