Steam Error Code 15 — What It Means & How to Fix It

What Does This Error Mean?

Steam Error Code 15 means 'Not logged on' or 'No connection' — the Steam client tried to perform an action that requires a network connection to Steam's servers, but the connection was not available. This error appears most often when Steam is running in Offline Mode, when your internet is down, or when Steam's servers are temporarily unreachable. Switching out of Offline Mode or restarting your network usually resolves it quickly.

Affected Models

Steam (Windows)
Steam (macOS)
Steam (Linux)

Common Causes

Steam is running in Offline Mode — the most common cause by far
Your internet connection is down or disconnected
A firewall or antivirus is blocking Steam from reaching the network
Steam's servers are experiencing a temporary outage
Steam's network configuration files have become corrupted, preventing a proper connection

How to Fix It

Check if Steam is in Offline Mode. Open Steam and look at the top menu bar. If you see 'Go Online' under the Steam menu, you are in Offline Mode. Click 'Go Online' to reconnect.

Offline Mode is the number one cause of error code 15. Steam sometimes enters Offline Mode automatically if it detects a connection problem during startup.
Verify your internet connection. Open a web browser and load a website. If web browsing does not work, your internet is the problem — restart your router and modem (unplug for 60 seconds, then reconnect).

Steam requires a stable internet connection for anything involving your account, store, or multiplayer. Offline single-player games can often run without a connection.
Check if Steam is blocked by Windows Firewall or your antivirus software. Go to Control Panel > Windows Defender Firewall > Allow an app or feature through Windows Defender Firewall. Ensure steam.exe and steamwebhelper.exe are on the allowed list for both Private and Public networks.

After a Windows update or antivirus update, Steam's firewall permissions can be revoked automatically.
Clear Steam's network cache. Close Steam completely (check the system tray and right-click the Steam icon > Exit). Navigate to your Steam folder (usually C:\Program Files (x86)\Steam) and delete the file called 'ClientRegistry.blob'. Reopen Steam.

ClientRegistry.blob stores network and account configuration. A corrupted version of this file can prevent Steam from connecting even when the network is fine.
Flush your DNS cache. Open Command Prompt as Administrator (right-click the Start button > Windows Terminal (Admin) or Command Prompt (Admin)) and type: ipconfig /flushdns. Press Enter, then reopen Steam.

Stale DNS cache entries can prevent Steam from resolving its server addresses. Flushing DNS forces a fresh lookup and often fixes persistent connection errors.

When to Call a Professional

Error code 15 is a network connectivity issue. No professional repair is needed. If your internet is working and Steam still shows error 15, contact Steam Support at help.steampowered.com.

Frequently Asked Questions

Can I play games while Steam shows error code 15?

Yes — if the games do not require an internet connection. Switch to Offline Mode (Steam menu > Go Offline) to play single-player games you have already installed. Multiplayer games, games that require online DRM, and anything that involves the Steam store or your account will not work in Offline Mode.

Steam goes online but error 15 comes back later — why?

An intermittent internet connection is usually the cause. Steam maintains a persistent connection to its servers while running. If your Wi-Fi drops briefly, Steam loses the connection and may trigger error 15 before it can reconnect. Switching to a wired ethernet connection usually eliminates intermittent Steam connection errors.

Is error code 15 the same as error 118?

They are similar but slightly different. Error 15 means Steam is 'not logged on' — the connection was never established or was explicitly turned off (Offline Mode). Error 118 means Steam's connection actively failed while attempting to connect. Both indicate a network problem, but error 15 is more often a Steam configuration issue while error 118 is more often a firewall or ISP issue.