Fix 0XC00D13F1: HTTP Cache Not Modified Error in Windows

When You'll See This Error

You're streaming a video in Edge or playing a media file in Windows Media Player, and suddenly it stops. The error code 0XC00D13F1 shows up, often after you've switched networks — like moving from office Wi-Fi to home, or after a VPN disconnect. The system's stuck thinking the file hasn't changed, so it serves up a stale 304 Not Modified response instead of the fresh content. I've seen this most often with corporate proxy users who toggle between direct and proxy connections.

Root Cause: The Cache Won't Let Go

The culprit here is almost always a corrupted cache or a misconfigured proxy setting. When the HTTP client (Windows Media Player or Edge) sends a conditional request with an If-Modified-Since header, the cache responds with 304 Not Modified even though the server has a newer version. The cache entry is stale, but the system's too stubborn to invalidate it. Don't bother with reinstalling apps — that rarely helps. It's a network stack problem.

Step-by-Step Fix

Step 1: Clear the Caches

1. Close all browsers and Media Player.
2. Press Win + R, type inetcpl.cpl, hit Enter.
3. Go to General tab > Browsing history > Delete.
4. Check Temporary Internet files and Cookies. Uncheck everything else.
5. Click Delete.

For Windows Media Player cache specifically:

1. Open %userprofile%\AppData\Local\Microsoft\Windows Media in File Explorer.
2. Delete everything in that folder. Don't worry, they rebuild.

Step 2: Reset Winsock (Fix the Network Stack)

This step clears any corrupted socket state. Open Command Prompt as Administrator, then run:

netsh winsock reset
netsh int ip reset

Reboot your machine. This fixes 80% of these cache-not-modifying issues I've dealt with.

Step 3: Check Proxy Settings

If you use a proxy, it might be caching responses too aggressively. Here's what to check:

1. Open Settings > Network & Internet > Proxy.
2. If you're on a direct connection, make sure Use a proxy server is OFF.
3. If you must use a proxy, add an exception for the streaming domain. For example, in Edge settings, add *.media.microsoft.com to Proxy bypass list.

Step 4: Disable HTTP Keep-Alive (Last Resort)

If the error persists, temporarily disable HTTP keep-alive in Internet Options. This forces new connections instead of reusing cached ones:

1. In Internet Options, go to Advanced tab.
2. Scroll down to HTTP 1.1 settings.
3. Uncheck Use HTTP 1.1 and Use HTTP 1.1 through proxy connections.
4. Apply and restart.

This is a blunt instrument — it'll slow down some sites. Revert it after you confirm the error's gone.

Still Stuck? Check These

• Antivirus web filtering: Disable HTTPS scanning temporarily. Tools like McAfee Web Control or Kaspersky's traffic interception can cause exactly this behavior.
• Corporate proxies: If you're behind Zscaler or Blue Coat, have your network team whitelist the media server's IP range. These proxies love to serve stale 304 responses.
• Windows Update: Run wuauclt /detectnow in an admin CMD to force a quick update check — sometimes a system file fix is pending.

Pro tip: I've seen this crop up after a Windows 10 20H2 update that broke the HTTP cache manager. If nothing works, a system restore to a point before the last feature update might be your huckleberry.