@Dhm (Dhm) posted a new topic, subject "4.12.3 Editor won't launch". It read:

   I'm having issues starting up my editor since I installed the latest hotfix (4.12.3). After pressing the launch button it freezes on “Running” and never boots up an editor. (You can still find and close it in the Task Manager however)
    
    Any reason why this may be happening?
    
    Edit: Other versions (4.10 & 4.11) come with the same results, of exactly nothing happening…
    
    Resolved! I believe it was simply solved by rebooting

To which @Si_Thu (Si Thu) replied

    if you cant open other versions as well, it seem that the problem is on user side rather than the engine itself. You might have recently uninstalled or deleted something that the engine rely on. Try the following, may be it will help.
    
      * Restarting your pc
      * Reinstalling the Unreal Engine Pre-requesties
      * Reinstall/update your graphic drivers
      * Update your pc through window updates
      * Uninstalling the engine & the Launcher, and reinstalling it again. (i'm pretty certain uninstalling them won't remove your project files, but its always safe to make backup)
    
    
    
    I hope one of these solve your problem.

To which @Adam_Davis (Adam Davis) replied

    Hi Dhm,
    
      * Does this occur in a clean, blank project with no additional content or only in a specific project?
      * What steps are you taking to reproduce this on your end?
      * Can you post your dxdiag here so I can take a look?

To which @Adam_Davis (Adam Davis) replied

    Hi Dhm,
    
    We have not heard from you in several days. I am marking this as answered for tracking purposes. If you are still experiencing this error, please comment with the requested information.

@nomorejazz (nomorejazz) replied

    If running on anything older than Windows 10, you'll need this update from Microsoft. After installing the editor, it would not launch and I got the error about the missing .dll file: “api-ms-win-crt-string-l1-1-0.dll is missing” … a quick search lead me to this link:
    
    support.microsoft.com
    
    ### Update for Universal C Runtime in Windows
    
    Describes an update for Universal C Runtime (CRT) in Windows 8.1, Windows RT 8.1, Windows Server 2012 R2, Windows 8, Windows RT, Windows Server 2012, Windows 7 SP1, Windows Server 2008 R2 SP1, Windows Vista SP2, or Windows Server 2008 SP2.
    
    Installed the update and worked perfectly.


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