# Does ForceOneChunkPerFile Actually Assign Files to the Lowest Numbered Chunk? 

**URL:** <https://forums.unrealengine.com/t/does-forceonechunkperfile-actually-assign-files-to-the-lowest-numbered-chunk/2745563>\
**Category:** Platform & Builds\
**Tags:** pak-file, Chunking, unreal-engine, Packaging, question\
**Created:** [August 21, 2026, 3:52pm UTC](https://forums.unrealengine.com/t/does-forceonechunkperfile-actually-assign-files-to-the-lowest-numbered-chunk/2745563 "2026-08-21T15:52:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![euOnmyoji](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@euOnmyoji](https://forums.unrealengine.com/u/euOnmyoji)\
**Post date:** [August 21, 2026, 3:52pm UTC](https://forums.unrealengine.com/t/does-forceonechunkperfile-actually-assign-files-to-the-lowest-numbered-chunk/2745563/1 "2026-08-21T15:52:53Z")

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I have assets that are assigned to specific chunks for individual packaging, but there’s also a fallback label that catches all assets. This means some assets end up in multiple chunks simultaneously.

I have several chunk pak files, but I’m experiencing issues where:

1. Some chunks are excessively large
2. Some chunks aren’t actually being written (empty or missing)

I was reviewing the packaging code and noticed that `bForceOneChunkPerFile` is documented to assign files to “the lowest number requested” chunk, but the implementation uses `HashSet<ChunkDefinition>` which has undefined enumeration order.

I’m wondering if anyone has actually observed files being assigned to the wrong chunk when this setting is enabled?