Hi
Since everyone is probably going to install UE4.26 and many of us realize that we may have too little disk space (again!) - why not share some tips on how to clean up the stuff that UR4 uses.
I realize that this may not be the very best solution, but deleting the content of C:\Users\AppData\Local\UnrealEngine\Common\DerivedDataCache may be a temporary solution - as the data stored here will be regenerated as you go along and reload your projects. You Could also move the data to the secondary HD, but it takes some extra considerations. Read more Derived Data Cache?