Note: Version 4.26+ has been perfected and does not need this method.
The "space method"
method can speed up compilation time by about three times in some cases.
Operation process:
1. First find the Win64 file in the Unreal Engine installation folder.
Everyone's installation location is different. This is my installation file path: E:\UE\UE_4.20\Engine\Binaries\Win64
Find the Win64 file below.
2. Find an UnrealHeaderTool.target in the Win64 file. Open with Visual Studio.
3. After finding the file and opening it, click on the first line with the mouse
After "TargetName": "UnrealHeaderTool", add a space.
Save, exit, and reopen the project. Compilation speed has been significantly improved.