If you work with the Unreal Engine 4 you probably know what Derived Data Cache is. There is a nice article about it: Derived Data Cache | Unreal Engine Documentation which also explains you how to change the location you use to share your DDC with other people. But what if you want to change the location of the DDC itself? Your local cache. By default, the local cache uses your Engine/DerivedDataCache folder. What if you want to move it to another location? For example, to a separate HDD. You can! There’s another environment variable you can set: UE-LocalDataCachePath, just set it to any path you want!
Note #1: I haven’t tested it on a binary build of the engine (the one you download from the Launcher) but I assume that it will not work. For more details, open Engine/Config/BaseEngine.ini, find a section called [InstalledDerivedDataBackendGraph] and compare it to the section called [DerivedDataBackendGraph].
Note #2: This will change data cache location for ALL your compiled copies of the engine, which may result in conflict if you have multiple copies on your machine!