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Fixed
Fixed in 6000.3.0b1
Votes
0
Found in
2021.3.50f1
2022.3.60f1
6000.0.45f1
6000.1.0b13
6000.2.0a8
6000.3.0a1
Issue ID
UUM-102672
Regression
No
BuildPipeline.BuildAssetBundles rebuilds unchanged assets in an AssetBundle when called after relaunching the Editor if these assets were modified and rebuilt in the previous session
How to reproduce:
1. Open the attached “IN-90295” project
2. Open the “SampleScene”
3. In the Project window, create a new MonoBehaviour script
4. Select any Prefab from the “Prefab” folder
5. In the Inspector, attach the created script to the Prefab
6. From the top menu bar, select Tools > Build and wait for the build process to complete
7. Relaunch the Unity Editor
8. Open the Console window
9. From the top menu bar, select Tools > Build and wait for the build process to complete
10. Observe the Console window
Expected result: No messages are printed in the Console
Actual result: Data for the previous and current build info for the changed Asset’s bundle is printed, showing the TypeTreeHash values are different between the initial and rebuilt versions of the bundle
Reproducible in: 2021.3.50f1, 2022.1.0a1, 2022.3.60f1, 6000.0.45f1, 6000.1.0b13, 6000.2.0a8
Reproducible on: Windows 10 (by User), Windows 11
Not reproducible on: No other environments tested
Note: While rebuilding the bundles, AssetFileHash, MD5, and CRC hashes remain consistent. However, the TypeTreeHash changes despite no alterations being made to the assets.
Comments (1)
-
AndrewSkow
Aug 25, 2025 14:41
We are working on a fix for this for 6.3.
The problem was related to a non-deterministic sorting of MonoBehaviours when calculating the typetree hash for an AssetBundle (Specifically it was sorting by their instance ids instead of a more stable value like the class type string).
For older versions of Unity there is a flag available that can act as a workaround, see
https://docs.unity3d.com/ScriptReference/BuildAssetBundleOptions.IgnoreTypeTreeChanges.html
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Resolution Note (fix version 6000.3.0b1):
Changed order of ClassTypes in AssetBundle .manifest