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Under Consideration for 6000.4.X

Votes

12

Found in

6000.0.61f1

6000.2.10f1

6000.3.0b8

6000.4.0a3

Issue ID

UUM-125349

Regression

Yes

GameObject appears as "deleted gameobject" in Hierarchy when importing a model using a custom script

Mono

-

How to reproduce:
1. Open attached project "IN-121121"
2. Open "LoadModelFromZipFile" Scene
3. Enter Play Mode
4. In Game View, press "Load Model"
5. Select the provided "IN-121121_sampleModel.zip" file and press Open
6. Observe Hierarchy
7. Select "deleted gameobject" in Hierarchy
8. Observe Console

Expected result: GameObject name is set to the filename and selecting it in the Hierarchy does not produce any errors
Actual result: GameObject shows up as "deleted gameobject" and clicking on it produces errors in the Console

Reproducible with: 2023.2.0a10, 6000.0.61f1, 6000.2.10f1, 6000.3.0b8, 6000.4.0a3
Not reproducible with: 2023.2.0a9

Reproducible on: Windows 10 (by user), Windows 11
Not reproducible on: No other environments tested

Notes:
- issue also reproduces with other models
- custom script is part of "Lightweight FBX Importer" third-party package
- exiting Play Mode or closing the Editor after interacting with the "deleted gameobject" results in the Editor crashing on "Coroutine::CleanupCoroutineGC" and "Object::SetCachedScriptingObject"
- "ArgumentException: GCHandle value belongs to a different domain" Error is thrown when selecting the "deleted gameobject" in Hierarchy
- "SerializedObjectNotCreatableException: Object at index 0 is null" Error is thrown repeatedly when selecting the "deleted gameobject" in Hierarchy
- "InvalidCastException: Specified cast is not valid." Error is thrown repeatedly when selecting the "deleted gameobject" in Hierarchy

Comments (3)

  1. rickomax

    Dec 29, 2025 11:08

    It looks like the issue was caused by a mismatch in the return data type in the read_fn method of ufbx_stream_safe.cs. I wasn’t using my UFBX_32_BITS guard on the return value. In previous Unity versions, this didn’t seem to cause any issues, but when combined with my threaded loading mode (enabled via the USE_THREADS compiler directive), it ended up causing domain issues that corrupted the Unity heap.

    I’ve removed threaded loading for now, until it’s properly fixed, and added the correct guard to the read_fn function.

    All of these changes are currently awaiting Asset Store approval in version 1.1.2.

    Best regards,
    Ricardo Reis

  2. rickomax

    Dec 27, 2025 09:36

    I am the Lightweight FBX Importer developer and am available to help with anything Unity needs to fix this issue.

  3. thesanketkale

    Dec 21, 2025 03:14

    Hey @Unity team, what is the ETA for this fix? Our app update rollout is currently blocked due to this issue.

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