How to Fix "League of Legends Update Stuck on Checking Size"

A League of Legends update freezing on “Checking Size” is a common issue, usually caused by a hiccup in the Riot Client’s update process. This guide provides a clear sequence of solutions to resolve it.

🛠️ Troubleshooting Roadmap

Start with the simplest fix and proceed in order.

Fix	Primary Action	Best For
Fix 1	Repeatedly click the update button in the Riot Client.	A quick, first attempt that can jolt the updater.
Fix 2	Fully restart the Riot Client via Task Manager.	Clearing a frozen or corrupted client process.
Fix 3	Repair the Riot Client through its settings.	Fixing underlying file corruption causing the hang-up.

📝 Step-by-Step Solutions

Fix 1: Force the Update by Repeated Clicking

This can manually advance the updater past a stuck point.

Open the Riot Client and log in.
Select “League of Legends” on the left sidebar.
Keep clicking the “Update” button multiple times in succession. This simple action can sometimes force the process to continue.

Fix 2: Perform a Clean Restart of the Riot Client

A full restart clears the client from memory, resolving many temporary glitches.

Open the Task Manager (Ctrl + Shift + Esc).
Go to the Details tab.
Find all Riot-related processes (e.g., RiotClientServices.exe, RiotClientUx.exe).
Right-click each one and select “End task” or “End process tree.”
Relaunch the Riot Client as an administrator and attempt the update again.

Fix 3: Repair the Riot Client

If the above fails, the client’s installation may be damaged and need repair.

In the Riot Client, click your profile icon (top-right) and go to Settings.
Select “League of Legends” from the list.
Uncheck “Enable auto-update.”
Click the “Repair” button and confirm with “Start Repair.”
Once complete, close Settings, select LoL, and click “Update.”

💡 Why This Happens & Pro Tips

Updater Mechanics: The “Checking Size” phase verifies local files against the server. Network timeouts, corrupted temporary files, or a buggy client can cause it to hang.
Run as Administrator: Always run the Riot Client with administrator privileges (right-click its shortcut > Run as administrator). This ensures it has necessary system permissions.
Check Antivirus/Firewall: Temporarily disable your antivirus or firewall to test if they are blocking the Riot Client’s connection to update servers. If so, add the Riot Games folder to the exclusion list.
Use Hextech Repair Tool: For persistent issues, Riot’s official Hextech Repair Tool can automate many advanced fixes like DNS flushes and network config resets.

❓ Frequently Asked Questions (FAQ)

Will repairing the client delete my settings or data?
No. The Repair function only checks and replaces core game and client files. Your in-game settings, friend list, and installed custom skins (if using authorized tools) are typically preserved.
Should I try Fix 2 (Task Manager) before Fix 1?
Yes. Fix 1 is the simplest “quick try,” but Fix 2 is often more reliably effective as it ensures a completely fresh client state. You can try them in either order, but ending the tasks is a solid second step.
What if none of these work?
The next steps are to:
1. Use the official Hextech Repair Tool.
2. Perform a clean reinstall: Uninstall both LoL and the Riot Client via Windows Settings, delete the remaining Riot Games folder in C:\, then download a fresh installer from the official website.
How can I prevent this in the future?
Ensure your Riot Client and Windows are up to date. Running the client as administrator and maintaining a stable internet connection during updates also helps.

Final Recommendation: Start with Fix 2 (Task Manager restart) as it’s a clean and effective first step for most users. If the problem persists, proceed directly to Fix 3 (Client Repair). This sequence resolves the vast majority of “Checking Size” hangs.