FIX: Unreal Engine 4 won’t launch on Windows & Mac

Aleksandar Ognjanovic
by Aleksandar Ognjanovic
Troubleshooting Expert
Aleksandar's main passion is technology. With a solid writing background, he is determined to bring the bleeding edge to the common user. With a keen eye, he always spots the next big thing surrounding... Read more
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  • Many developers stated that they cannot open Unreal Engine 4 on Windows and Mac.
  • If Unreal Engine 4 doesn't open, you should run it with the administrative permission.
  • You should check your third-party antivirus solution and disable it, or even remove it completely.
  • When a Windows update caused the issue, use the rollback option by following our guide below.
How to fix the Unreal Engine 4 won't launch on Windows & Mac
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Unreal Engine is rather important for so many developers. And, since it’s free, Unreal Editor and its current version, UE 4, are a must-have software in the business of development.

It works on well on the latest iteration of Windows 10, but there are some apparent issues at hand for some users. Namely, they were unable to open the Unreal Engine 4.

We prepared some solutions for this problem below, so make sure to check them out.

What to do if Unreal Engine 4 won’t launch on Windows & Mac?

  1. Run the UE 4 as admin
  2. Disable the antivirus
  3. Verify the installation
  4. Reinstall the Unreal Engine client
  5. Rollback Windows 10

1. Run the UE 4 as admin

  1. Open the Epic Launcher client, and select the Unreal Engine tab.
  2. Under the Unreal Engine 4, expand the drop-down menu and create the desktop shortcut.unreal engine 4 won't open on Windows 10
  3. Right-click on the desktop shortcut, and open Properties.
  4. Choose the Compatibility tab.
  5. Check the Run this program as an administrator box, and confirm changes.unreal engine 4 won't open on Windows 10

In most reports describing this issues, users were able to run Unreal Engine 4 without issues until it suddenly stops working.

This implies that some system changes were made. Some changes which evidently disrupted the game installation.

The most common reason is Windows Update (major updates especially), which seemingly broke both Epic Launcher and Unreal Engine 4.

The first step we suggest is trying to run the Unreal Engine client with the administrative permission.

2. Disable the antivirus

  1. Type Control in the Search bar, and select Control Panel from the list of results.
  2. With the Category view, choose to Uninstall a program.unreal engine 4 won't open on Windows 10
  3. Remove the antivirus completely.
  4. Restart your PC and try running the Unreal Engine 4 again.

Another possible reason for the malfunction of Unreal Engine 4 is a third-party antivirus. Judging by user reports, the re-occurring culprit for this is the ESET Internet Security solution.

Many of them tried disabling it, but the only thing which presented a permanent resolution is removing the antivirus completely.

3. Verify the installation

  1. Open the Epic Launcher, and choose the Unreal Engine tab.
  2. Expand the drop-down menu and click Verify.unreal engine 4 won't open on Windows 10
  3. Wait until everything is done.

Before we move to the reinstallation procedure, it’s worth trying to verify the integrity of the Unreal Engine 4 installation files.

You can use the built-in tool on Epic Launcher to check for the corruption within the installed files.

4. Reinstall the Unreal Engine client

If the installed files and the files from associated applications get corrupted, the client won’t start for obvious reasons.

Could something like that happen after the major Windows 10 update? Possibly. That’s why the reinstallation is another step you should follow through.

In addition, we suggest a clean uninstall which includes clearing everything (registry entries, too) assigned to Epic Launcher and Unreal Engine 4, respectively.

We already explained how to perform a clean uninstall in the second solution, just don’t forget to back up your projects.

5. Rollback Windows 10

  1. Open the Settings app, and choose Update & Security.unreal engine 4 won't open on Windows 10
  2. Select Recovery.
  3. Click Get started under the Go back to the previous version of Windows 10.unreal engine 4 won't open on Windows 10

That’s it. Don’t forget to share your questions or suggestions with us in the comments section below. We look forward to hearing from you.

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