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Fixed in 2020.1.X

Fixed in 2018.4.X, 2019.2.X, 2019.3.X



Found in






Issue ID




Re-serialization make changes to Nested Prefabs

Asset - Database


Steps to reproduce:
1. Download project
2. Open project with deleted Library
3. In toolbar select Repro -> Resterilize. Will resterilize all prefabs, forcing them to be resaved.
4. Check changes in TortoiseHG
5. Notice that some of the prefabs were change
5. Close and reopen the project
6. Resterilize once more
7. Check changes in TortoiseHG
8. Notice that second reserialization revert change prefabs
9. Re-serializing third time won't make any changes until the Library folder is removed.

Expected results: Serialization should not modify prefabs
Actual results: Serialisation modifies prefabs

Reproduced with: 2019.3.0a7, 2019.2.0b7, 2019.1.8f1, 2018.4.3f1

With the original project re-serialization, constantly modifies some of the prefabs, there is no need to delete the Library folder or reopen the project.

Comments (7)

  1. mariozhou

    Aug 31, 2023 09:51

    In the 2020.3.25f1 version, we still suffer from this issue.
    Any progress on this?

  2. WookieWookie

    Dec 02, 2021 19:06

    I had this issue with a heavily nested prefab. I had made a change to add AspectRatioFitter, and suddenly all the nested instances' parents were showing up as changed with every save.

    After trying several things, I realized the prefab was hanging off the edge of the Canvas in prefab mode, and anchored left. So I anchored it center and moved it to the middle of the page, and the issue stopped.

    I suspect ASF was having trouble reporting its size to nested instances.

  3. DevCase3DUnity

    Feb 02, 2021 14:15

    In which version of 2020.1 is this fixed? I have gone through Release Notes of each version and haven't found this issue in the known issues.
    I am still seeing this problem in 2020.1.6f1 version.

  4. OndrejP

    Oct 21, 2019 14:50

    Same here, exactly same behavior, ordering of modifications changes. (Unity 2019.2.9f1)

    It's big issue for us, because we use nested prefabs heavily and this change triggers reimport of all dependent prefabs, which can take minutes. Worse this happens when prefab is clicked in project, because it opens it in inspector and then it saves it right away.

    Naive approach to fixing this seems like sorting modifications by property path.

  5. TunnelVisionGames

    Oct 15, 2019 11:57

    Happens in 2019.2.1f1 and is very annoying, because saving can now take multiple minutes, so we have to be very aware of when we press Ctrl+S.

  6. mcarriere

    Oct 08, 2019 15:07

    We're seeing this in 2019.2.0f1 as well.

  7. ISanchezV

    Sep 13, 2019 13:00

    I have experienced this issue on every LTS release so far (currently 2018.4.8f1)

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