14.9.2 Will not launch - Prequisites failing around LauncherPrereqSetup_x64.msi - error message URL points to other error messages how do I resolve?

[SvenGG]

UE4 Was working fine prior to the latest update, but now it won’t launch.

Expected Behavior
Launching UE 14.9.2 launches the software.

Observed Behavior
The following series of errors occurs:

Attempted Solutions

• Re-installing DirectX
• Repairing / Re-installing Visual C++ versions
• Restarting computer
• Checking for Windows updates
• I also tried navigating into the Unreal folder to one of the file paths mentioned and launching a file there, which failed with the same first message, but gave me this log file: Log from prerequisites failure when launching UE4 · GitHub maybe that could help someone identify the problem / potential solution?

Summary
I have tried following the error code which links to help articles with different error codes. I can’t find anywhere to directly download the LauncherPrereqSetup_x64.msi file so that I could point UE4 to it. Pretty desperate for a solution at this point. Thanks in advance for any help.

[SvenGG]

I finally fixed the issue:

• There is a string of characters inside brackets: {} that pops up during the error.
• Copied that string and searched for it in regedit.
• Removed all entries containing that exact string.
• Ran CCleaner

UE4 Launches!