The short answer
Usually, after a check. Might hold something you care about. Look inside before removing it.
What is it?
Recent Unreal Engine 5 versions use a local cache server, Zen, to store derived data such as compiled shaders and cooked assets. Its storage lives in ~/Library/Application Support/Epic/UnrealEngine/Common/Zen. Typically tens of GB.
The local cache server's storage. Quit Unreal first; it is rebuilt, but the next project opening is slow.
What happens if you delete it?
Zen rebuilds its storage as projects are opened, so the next opening of each project is much slower while data is regenerated. Project files are not affected.
How to remove it properly
Quit Unreal Editor first and make sure the Zen server (zenserver) is no longer running, then move the folder to the Trash in Finder (Go › Go to Folder… ~/Library/Application Support/Epic/UnrealEngine/Common/Zen).
Quit the app that uses it, then move it to the Trash. Empty the Trash when you’re sure.
Before you delete it
Deleting it while the Zen server runs can corrupt the cache; quit Unreal and wait for the server to stop.
How MoreRoom helps
MoreRoom recognises this item and labels it “Review first”: it shows what’s inside, its size and last use, so you can decide. Nothing is removed without your say, and everything goes to the Trash first, with Undo.
Frequently asked questions
Is it safe to delete Unreal Engine’s Zen cache folder?
Usually, after a check. Might hold something you care about. Look inside before removing it. Zen rebuilds its storage as projects are opened, so the next opening of each project is much slower while data is regenerated. Project files are not affected.
Will Unreal Engine Zen cache come back after I delete it?
Yes. Zen rebuilds its storage as projects are opened, so the next opening of each project is much slower while data is regenerated. Project files are not affected.
How do I remove Unreal Engine Zen cache properly?
Quit Unreal Editor first and make sure the Zen server (zenserver) is no longer running, then move the folder to the Trash in Finder (Go › Go to Folder… ~/Library/Application Support/Epic/UnrealEngine/Common/Zen).