Local file format is not compressed. Solution?

Hello, I’m currently trying to package my build for shipping, but I keep getting an error message of a local file format not being compressed. Any solutions or directions on where to find the local file or where in UE5 I can find it?

UATHelper: Packaging (Windows): LogZenSerialization: Error: Local file ‘:?#:8808’ format is not compressed
UATHelper: Packaging (Windows): LogDerivedDataCache: Display: ZenLocal: Invalid response received from GetCacheRecords RPC: 1 results expected, received 0, from POST http://[::1]:8558//z$/$rpc → OK (200)
PackagingResults: Error: Local file ‘:?#:8808’ format is not compressed

Hello there @Samurai_X575!

Checking your log extract, I think the critical lines are the following:

LogZenSerialization: Error: Local file ‘:?#:8808’ format is not compressed
ZenLocal: Invalid response received from GetCacheRecords RPC: 1 results expected, received 0

From what I could find around the community, this issue is tied to a conflict between UE’s ZenServer, and your current DDC’s contents. In short, your local cache is invalid or corrupted, and the engine is not being able to read the data due the lack of the expected compression header.

The fix should be pretty straight forward, just close UE, navigate to your project’s main directory, and to the engine’s local data, and delete the following folders from both locations:

%LOCALAPPDATA%\UnrealEngine\Common\DerivedDataCache
%LOCALAPPDATA%\UnrealEngine\5.6\DerivedDataCache
<YourProject>\Saved\DerivedDataCache

After that, make sure that no processes tied to Zen are still active in the background (simply check the Task Manage for any “Zen” activity). Once that’s done, re-open your project. And before attempting to pack again, go to your project settings, and ensure that Local DCC is enabled. Now, test packaging again.

If the issue persists after these changes, the other possible cultrip could be a cached asset, something large, like a landscape, or a significant background object. At that point, check the full log, and look for any calls related to any specific assets present in your scene, then re-import them.

Finally, it’s always useful to check UE’s documentation on the matter, to ensure your Zenserver’s functionality is properly setup: