For Steam:
- Open the Steam client > Go to Library.
- Click on Call of Duty: MWII from the left pane.
- It’ll automatically search for the available update.
- If there is an update available, click on Update.
- Wait some time to install the update.
- Once done, close the Steam client.
- Finally, reboot your PC to apply changes and launch the game again.
For Battle.net:
- Open the Battle.net client > Go to All Games.
- Click on Installed > Click on COD: MWII.
- Now, click on the Settings icon.
- Select Check for updates > If there is any update, click on Update.
- Once done, make sure to close the Battle.net client.
- Finally, reboot your PC to apply changes, and then try launching the game again.
4. Repair the Game Files
Corrupted or missing game files on the PC can eventually trigger multiple issues with the game launching or performance whatsoever. It’s better to verify and repair the installed game files on the PC depending on which client you’re using to play the game. You can follow the steps below to repair the game files easily.
For Steam:
- Launch the Steam client > Click on Library.
- Right-click on Call of Duty: MWII from the list of installed games.
- Now, click on Properties > Go to Local Files.

- Click on Verify Integrity of Game Files.
- You’ll have to wait for the process until it gets completed.
- Once done, just restart your computer.
For Battle.net:
- Open the Battle.net client on your PC.
- Head over to the Library > Click on COD: MWII.
- Click on Options > Select Scan and Repair.
- Choose to Start Scan > Wait for the process to complete.
- Once done, close everything, and reboot the PC.
5. Check the Internet Connection
You should also try checking out the network connection on your side to ensure there is no internet speed or stability issue. An unstable and poor internet connection might greatly trouble you regarding the game’s server connection or multiplayer gameplay. If you’re using the Wi-Fi network, try switching to the Wired (Ethernet) or vice versa to cross-check the issue. You can also contact your service provider to check the internet-related issues.
6. Check Activision Online Services
Mostly the COD Modern Warfare 2 Assert Error ‘Assertion Failed Bad Event Handle’ appears due to the high traffic or server outage in your region when you’re trying to play. It’s better to check the official Activision Online Services page and select the specific game from the list to get to know if servers are having issues or not. The server outage or maintenance typically restricts the game launching or connecting to the servers in most cases until the problem is solved.
7. Close Background Running Tasks
Unnecessary background running tasks or programs can eat up a lot of system resources like CPU or Memory usage literally reducing system performance. Hence, the startup crashing, lagging, and not loading issues appear quite often. Simply, close all the third-party unnecessary background running tasks completely. To do this:
- Press the Ctrl+Shift+Esc keys to open up Task Manager on the PC.
- Now, click on the Processes tab > Click to select the unnecessary task. [Memory consuming task]
- Click on End Task to close it > Do the same steps for other unnecessary third-party tasks too.
- Once done, restart your system to apply changes.
If none of the methods worked for you then make sure to contact Activision Support for additional help. You should also create a support ticket for the same to get a better resolution asap. The chances are high that developers will try investigating this issue and fixing the same. You might have to wait further to get it resolved.
That’s it, guys. We assume this guide was helpful to you. For further queries, you can comment below.