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Won't Fix

Votes

1

Found in

2018.3.0b12

Issue ID

1109334

Regression

No

"PPtr cast failed when dereferencing!" errors when opening an older project with a newer version while cache server is enabled

Asset - Database

-

How to reproduce:
Steps:
1. Setup remote Cache server in Unity editor
2. Replace the cache5.0 folder on your Cache Server with the attached one (cache5.0.zip)
3. Run Cache Server
4. Open attached project (fbx model and scene inside) with Unity 2018.3.1f1 (project - bug.zip)
5. Double click on "TestScene"
==>
"PPtr cast failed when dereferencing! Casting from PrefabInstance to Prefab!"

Also it is not possible to instantiate fbx

Note: Reproducible with Cache Server 2018.1.0f2 and 2019.1.0a12

Reproducible with: 2018.3.1f1
Not reproducible with: 2019.1.0a12

  1. Resolution Note (2019.1.X):

    After reviewing the related Zendesk ticket and some discussion, it appears the customer wants to be able to switch project back and forth between 2018.1.0f2 (specifically) and 2018.3.

    2018.1.0f2 writes some bad info into the asset, an issue which was already fixed in 2018.1.5f1.
    2018.3 requires the asset to be re-imported because of this.

    We do not support downgrading a project from 2018.3 to 2018.1. We cannot guarantee what will happen if a project is switched 2018.3 > 2018.1 > 2018.3.

    Later versions appear to be fixed because of further importer version updates. These cause the asset to be re-imported regardless.

    We recommend any one of the following workarounds:
    1) Not performing downgrade project version switching
    2) Upgrading 2018.1 to 2018.1.5f1
    3) Re-importing the asset each time when opened on 2018.3

Comments (1)

  1. radhat2009

    May 14, 2020 05:21

    I found it in 2019.3.13f1 Personal while working through the Sword and Shovels tutorial available on Unity Learn.
    This might help when double-clicking on the error it opened up the inspector and got a popup prompting for me to Rename Prefab File.
    "The Prefab file name must match the Prefab root GameObject Name. Once it was renamed I haven't seen the exception since.

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