Fix Steam Missing Content Manifest: Error 25/26 Guide

If Steam says “Missing content manifest” (error 25 or 26) when you try to launch or update a game, the fix is to clear the download cache and verify the game files. This usually happens after a forced shutdown, a failed update, or a corrupted download; the steps below resolve it in most cases without reinstalling the game.

What Causes the Missing Content Manifest Error

Steam uses a “content manifest” to track every file in a game’s installation. When you launch a game, Steam checks this manifest to verify that the files on your disk match the ones it expects. If the manifest is missing, corrupted, or out of sync, Steam cannot confirm the game is intact and refuses to start it.

Common triggers include:

• Steam crashes or your computer shuts down mid-update, leaving the manifest half-written.
• A game update is interrupted by a network drop, leaving a partial download that Steam can’t reconcile.
• Antivirus software quarantines or deletes a game file, causing the manifest to point to a missing file.
• Disk errors or a full hard drive corrupt the manifest file.
• Moving the game folder manually without using Steam’s built-in move feature.

The error message usually appears as “Missing content manifest” with error code 25 or 26. It can affect any game, but it’s more common with large, frequently updated titles like Counter-Strike 2, Dota 2, or PUBG.

Method 1: Clear the Download Cache

This is the first thing to try because it’s fast and often fixes the problem without touching your game files.

1. Open Steam and go to Settings (Steam menu on Mac, or the Steam button in the top-left on Windows).
2. Select Downloads from the left sidebar.
3. Click Clear Download Cache.
4. Steam will ask you to restart. Click Restart Steam.
5. After Steam restarts, you’ll need to log in again. Then try launching the game.

Clearing the cache doesn’t delete your games; it only removes temporary download data. If the manifest error was caused by a leftover partial download, this will clear it.

Method 2: Verify Integrity of Game Files

If clearing the cache doesn’t work, the next step is to force Steam to re-check the game’s files against the manifest.

1. In your Steam Library, right-click the game that shows the error.
2. Select Properties.
3. Go to the Installed Files tab.
4. Click Verify integrity of game files.
5. Wait for the process to finish. It may take a few minutes for large games.

Steam will compare every file on disk with the manifest. If it finds any missing or corrupted files, it will re-download them. This is the most reliable fix for a corrupted manifest because it forces Steam to rebuild the manifest from the server.

Method 3: Delete the Manifest File Manually

If verification doesn’t help, you can delete the manifest file itself. Steam will then recreate it on the next launch.

1. Exit Steam completely (right-click the tray icon and select Exit).
2. Navigate to your Steam installation folder (usually C:\Program Files (x86)\Steam).
3. Open the steamapps folder.
4. Find the file named appmanifest_.acf. The game ID is a number; you can find it by looking at the game’s store page URL (e.g., app/730 for CS2).
5. Delete that file.
6. Restart Steam. It will see the game as “not installed” and prompt you to install it. Choose the same drive/folder where the game already exists, and Steam will discover the existing files and re-create the manifest.

This is a bit more advanced but works when the manifest file itself is corrupted beyond repair. Make sure you don’t delete the game folder—only the .acf file.

Method 4: Disable Antivirus or Add Exceptions

Some antivirus programs mistakenly quarantine Steam game files, especially after an update. If the error started after you installed a new antivirus or ran a scan, this could be the cause.

1. Open your antivirus software and check the quarantine list for any files from the game folder.
2. If you find any, restore them and add an exception for the Steam folder (usually C:\Program Files (x86)\Steam).
3. Restart Steam and try launching the game again.

If you’re using Windows Defender, you can add an exclusion via Windows Security → Virus & threat protection → Manage settings → Exclusions.

Method 5: Check Disk Errors and Free Space

A failing hard drive or a full disk can cause manifest corruption. Check that you have at least 10 GB of free space on the drive where the game is installed (Steam needs room for temporary files).

On Windows, you can run chkdsk to check for disk errors:

1. Open Command Prompt as Administrator.
2. Type chkdsk /f and press Enter.
3. If prompted, type Y to schedule a check on next restart, then restart your PC.

On macOS, use Disk Utility → First Aid. If chkdsk finds bad sectors, back up your data and consider replacing the drive.

Frequently Asked Questions

Will I lose my game saves if I delete the manifest file?

No. The manifest file only contains metadata about the game’s file structure, not your save data. Saves are stored in your user data folder (usually Steam\userdata) or in the game’s own folder, and they are not touched by these steps.

Why does this error happen after a Windows update?

Windows updates can sometimes cause Steam to lose track of files, especially if the update restarts your PC while Steam is running. A forced shutdown mid-update is a common cause of manifest corruption. The same fix applies: verify files or delete the manifest.

Can I fix this without reinstalling the game?

Yes, in most cases. The methods above (clearing cache, verifying files, deleting the manifest) usually resolve the issue without a full reinstall. Reinstalling is a last resort if none of those work.

What does error 25 vs 26 mean?

Both errors indicate a missing content manifest, but error 26 often appears when the game is installed on an external or secondary drive that isn’t mounted. If you use an external drive, make sure it’s connected and set to auto-mount before starting Steam.

Does this affect all my games or just one?

Typically just one game, because each game has its own manifest. If you see the error on multiple games, it’s more likely a global issue like a corrupted Steam installation or a failing hard drive. Try clearing the download cache first, then verify files for each affected game.

Is there a way to prevent this in the future?

Always exit Steam properly before shutting down your PC, keep your drive healthy with regular checks, and make sure you have enough free space. Also, avoid manually moving game folders—use Steam’s built-in “Move Install Folder” feature (right-click game → Properties → Installed Files).

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