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Fixed in 2018.3.X

Fixed in 2019.1.X



Found in





Issue ID




Prefab's references are lost when modifying prefab

Scene Management


How to reproduce:
1. Open attached "" project
2. Go to Assets -> Scenes and open 'SampleScene'
3. Click on 'Spawner' and call 'Log' in the ContextMenu in the Inspector
4. Observe the Console
5. Go to Assets, open Enemy in Prefab Mode and edit it (e.g. change the position)
6. Repeat 3, 4 steps

Expected result: Console returns 'Enemy(Enemy)'
Actual result: Console returns 'null'

Reproducible: 2018.3.2f1, 2019.1.0a14, 2019.2.0a1
Not reproducible: 2017.3.0a1, 2017.4.18f1, 2018.3.0a11

Fixed in: 2018.3.6f1, 2019.1.0b4, 2019.2.0a6

Comments (49)

  1. hk1ll3r

    Apr 29, 2020 08:03

    happens in 2019.3.11f1.

  2. M4R5

    Apr 17, 2020 23:38


    2019.3.9f1: losing references to manually assigned `[SerializeField]` List<GameObject> elements on build

  3. josrodes

    Apr 09, 2020 17:00

    This is happening in 2019.3.0f6, is there a new Open case for this?

    Prefab nesting is doomed to fail at any point when the root is changed, the whole chain up goes haywire, I just had to unpack the second level to get it "fixed".

  4. Michael_Waltham

    Apr 07, 2020 10:36

    Still happening for us on 2019.3.6f1. This is a real project breaker halting a large portion of our dev. Any plans for this bug to be reopened soon?

  5. forcepusher

    Apr 07, 2020 05:39

    2019.3.8f1 still losing prefab variant references.

  6. ClockStone_Helmut

    Apr 02, 2020 10:50

    We get this too from time to time in 2019.3.6f1.

  7. Squoktapus

    Mar 31, 2020 11:16

    I noticed something similar via the cloud build.

    Cloud build is running latest 2019.3.6f1 whilst the latest version in the hub is 2019.3.7f1 (aside, but why the disparity?).

    Anyway binaries from the cloud build had lost prefab references and reverted to defaults. Which was quite difficult to diagnose as prefab references are not widely used. Specifically LayerMask and Layers were lost on prefabs after an upgrade. A clean build resolved it.

    We will beware upgrades and guard prefab references.

  8. AlexTuduran

    Mar 24, 2020 17:17

    Still happening in 2019.3.3f1 and it's a major issue for us. It holds us back seriously, as a complete project re-import lasts more than one hour (project size > 30GB). Make this your top priority, data loss is a deal-breaker.

  9. xjjon

    Mar 11, 2020 03:03

    Still happens for me. Not fixed!

  10. VirtualDestructor

    Feb 20, 2020 17:01

    This issue, or a very similar one, is still happening for me in Unity 2019.3

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