Mortal Kombat 1 Errors

Mortal Kombat 1's main problems are online: a generic 'server error' / 'connection lost' when joining matches, plus install failures. These are network errors — poor connection, firewall blocking, IPv6 issues, or corrupt files — not always an outage. Here's what each common problem means and the fastest fix.

Error codes

Server error / connection lost (online) You can't join or stay in online matches

Cause: A WB/NetherRealm outage, or on your side: poor connection, outdated network drivers, firewall blocking, or IPv6 routing.

Fix:
  1. Check WB Games Support and @MortalKombat for maintenance/outage first, and Downdetector for real-time reports.
  2. Allow Mortal Kombat 1 through Windows Defender Firewall on both Private and Public networks.
  3. Switch your connection from IPv6 to IPv4 (or enable IPv4 on your router if you only have IPv6).
Online not working / can't matchmake Servers are up but you still can't play online

Cause: Corrupt game files or a network glitch on your side.

Fix:
  1. Fully close MK1 (not just minimize), restart the PC, and relaunch.
  2. Verify Integrity of Game Files in Steam (Properties -> Local Files).
  3. Update your network driver and restart your router.
Mortal Kombat 1 won't install The install or update fails to complete

Cause: Insufficient disk space, corrupted download cache, or client issues.

Fix:
  1. Free up disk space and clear the Steam download cache (Settings -> Downloads -> Clear Download Cache).
  2. Run the launcher as administrator and move the library to a drive with more room.
  3. Verify the game files after the install completes.

Fixes that work for most Mortal Kombat 1 (PC, PlayStation 5, Xbox Series X|S, Nintendo Switch) errors

  1. Verify/repair the game files (Steam: Properties -> Installed Files -> Verify integrity; EA app/Epic/Ubisoft: Manage -> Repair) — this replaces corrupted files behind most crashes and fatal errors.
  2. Update your GPU driver with a clean install (use DDU), and install the latest Microsoft Visual C++ Redistributables (x86 and x64) plus the DirectX End-User Runtime — missing runtimes and stale drivers cause most launch crashes.
  3. Clear the DirectX Shader Cache (Windows Settings -> System -> Storage -> Temporary files, or Disk Cleanup) and delete the game's local shader/cache folder in AppData\Local, then relaunch.
  4. Disable overlays (Steam, Discord, GeForce Experience, EA, Epic) and any third-party antivirus/VPN, and add the game to your firewall and antivirus exceptions.
  5. Check the game's official server/status channels before assuming a local problem — many named connection errors are a maintenance window or outage and clear on their own.

FAQ

How do I fix the Mortal Kombat 1 server error / connection lost?

First check WB Games Support, @MortalKombat and Downdetector to rule out a real outage. If servers are up, allow Mortal Kombat 1 through Windows Defender Firewall on both Private and Public networks, switch your connection from IPv6 to IPv4 (or enable IPv4 on your router if you're IPv6-only), fully close and relaunch the game after a PC restart, and verify the integrity of the game files.

Why won't Mortal Kombat 1 install on PC?

Install failures usually come from low disk space, a corrupted download cache, or launcher issues. Free up disk space, clear the Steam download cache in Settings -> Downloads, run the launcher as administrator, and consider moving the library to a drive with more room. Verify the game files once the install finishes.

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