Modern Warfare 4 Crashing on Steam After the Season 1 Update? The Official Fix

Is this your crash?

This guide covers one exact problem: the game crashes at launch on Steam after you take the Season 1 update. That is the wording Activision uses in the official Season 1 patch notes, and the same crash sits on the official Known Issues page for Modern Warfare 4. If your game ran fine before November 6 and now closes as it starts, this is very likely your issue.

If your crash happens mid-match instead, or on a console, this page is not written for that case. Activision has not tied those crashes to this known issue, and the steps below are the Steam launch fix only. Do not let that stop you from step 1, though. A file check is safe on any PC copy of the game and it rules out damaged files in minutes.

Step 1: Verify the integrity of your game files in Steam

This is the first fix Activision gives, word for word, and it is the one to try before anything else. Steam compares the files on your PC with the clean copies on its servers and downloads a fresh copy of anything that is missing or damaged. On a big install the check can take a while, so let it finish.

1. Open Steam and go to your Library.
2. Right-click Modern Warfare 4 in the game list and choose Properties.
3. Click Installed Files on the left side of the Properties window.
4. Click Verify integrity of game files.
5. Wait for the check to reach 100 percent. If Steam finds bad files, it downloads clean ones on its own.
6. Launch Modern Warfare 4 and test whether the crash is gone.

The check does not touch your account, your unlocks or your progress. It only repairs the game files on your own drive. If the game opens after the check, you are done. Do not do step 2 just to be safe, because step 2 costs you a very large download for no extra gain.

Step 2: Uninstall, delete the leftover folder, then reinstall

Activision calls this the final workaround, and that word final matters. Only do this step if step 1 finished and the game still crashes at launch. A full reinstall of Modern Warfare 4 is a very large download, so start it when you have the time and the data to spare, not five minutes before a match.

1. Uninstall Modern Warfare 4 and Warzone through the Steam app. Both games, not just one.
2. Go to the folder where Call of Duty was installed on your PC. Open the steamapps folder, then the common folder inside it, and delete the leftover Call of Duty folder.
3. Reinstall Modern Warfare 4 in Steam.
4. Launch the game and test the launch more than once.

The folder delete in the middle is the step most players skip, and skipping it is the likely reason a plain reinstall sometimes changes nothing. Steam uninstalls the files it tracks. Old files left behind in that folder can survive and get picked up again by the fresh install. Delete the folder while both games are uninstalled, before you reinstall.

What Activision has confirmed, and what is still unknown

Here is the honest picture as of November 9, 2026. Activision has confirmed that the crash exists and that its team is investigating it. The patch notes add one more fact: the team is working directly with Steam on a resolution. That is all. No cause has been published, no number of affected players has been published, and no date for a fix has been published. Any site that gives you a cause or a fix date today is guessing. The full Warzone Season 1 patch notes are on the official Call of Duty site.

The Steam crash is not the only problem on the official Known Issues page. The same page lists these issues, which helps you tell a known game problem apart from a problem with your own PC:

Community-reported ideas: not confirmed by Activision

Search this crash online and you will find extra ideas from other players: turning graphics options like DLSS off, closing background tools, or changing network software. Read this part clearly: those ideas are player-reported only. Activision has not confirmed any of them for this crash, and this guide does not present them as fixes. Some of them change how your PC connects or runs other software, which can create new problems of their own.

If you try a community idea anyway, that is your call, and you do so at your own risk. Change one thing at a time, write down what you changed, and undo it if it does not help. The only two fixes Activision stands behind today are the file check and the reinstall above, in that order.

Back in the game? Warzone is now fully part of Modern Warfare 4, and its menus changed with Season 1. Our guide to the best Warzone settings covers the current PC and console menus, with the upscaler, shadow and field of view settings that give you the most frames.

MW4 Steam crash questions

Why is Modern Warfare 4 crashing on Steam after the Season 1 update?

Nobody outside the development team knows yet, and Activision has not published a cause. The crash is listed on the official Known Issues page as under investigation, and the Season 1 patch notes say the team is working directly with Steam on a resolution. Until a fix ships, the confirmed steps are the file check first and the reinstall second, exactly as printed above.

Will verifying my game files delete my progress?

No. The check only scans the game files stored on your PC and downloads clean copies of any file that is missing or damaged. It does not touch your Activision account, your unlocks or your progress, and you do not lose your settings in the game menu. It is the safest first step, which is why Activision lists it first.

Is there a hotfix coming for the MW4 Steam crash?

No date has been announced. As of November 9, 2026, Activision still lists the crash as under investigation, the November 7 patch notes contain no fix for it, and the official pages name no cause and no scale for the problem. This guide is checked daily and its status box is updated as soon as that changes.