Unity Issue Tracker - [WebGL] Build fails with "System.IO.IOException: The file is too long." when building with an asset that is over 2GB

In Progress

Fix In Review for 6000.3.X

Under Consideration for 6000.0.X, 6000.4.X, 6000.5.X

In Progress in 6000.5.X

Votes

2

Found in

6000.0.54f1

6000.1.13f1

6000.2.0b12

6000.3.0a3

6000.4.0a1

6000.5.0a1

Issue ID

UUM-112909

Regression

No

[WebGL] Build fails with "System.IO.IOException: The file is too long." when building with an asset that is over 2GB

Web Platform

-

Jul 28, 2025

How to reproduce:
1. Open the “unity-2gb-bug.zip“ project
2. Open the “terrain-demo“ scene
3. Build for WebGL

Expected result: Build does not fail
Actual result: Build fails with “System.IO.IOException: The file is too long. This operation is currently limited to supporting files less than 2 gigabytes in size.“

Reproducible with: 6000.0.54f1, 6000.1.13f1, 6000.2.0b12, 6000.3.0a3

Reproducible environment: macOS 15.4.1 (M4 Max), Windows 11 (Reporters)
Not reproducible environment: No other environment tested

Note: More information in the comments

Error:
Building Library/Bee/artifacts/WebGL/webgl.data failed with output:
System.IO.IOException: The file is too long. This operation is currently limited to supporting files less than 2 gigabytes in size.
at System.IO.File.ReadAllBytes(String path)

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