[Bug Report] weird 'ModuleNotFoundError' issue

[Shaw-Way]

Describe the bug

The program was running perfectly fine, but then it suddenly threw an error during one execution: AttributeError: module 'omni.usd' has no attribute 'UsdContext'. I followed the method in this link to delete the extscache, which made the original error disappear, but then another one appeared: ModuleNotFoundError: No module named 'omni.kit.usd'. I’ve reinstalled Isaac Lab and encountered this bug(ModuleNotFoundError: No module named 'omni.kit.usd') several times. Each reinstallation takes several hours — I'm about to go crazy.

[Shaw-Way]

I encountered this issue again !!!!!!

[Shaw-Way]

I tried this workaround. But it doesn't help.

[ealban-rai]

I'm facing quite similar issue:

2025-10-31 13:43:42 [6,320ms] [Error] [omni.kit.registry.nucleus.index_v2.index_sync] Syncing registry index failed for url: 'https://ovextensionsprod.blob.core.windows.net/exts/kit/prod/106/shared/v2'. Exception: Failed to connect to the registry: 'https://ovextensionsprod.blob.core.windows.net/exts/kit/prod/106/shared/v2'
2025-10-31 13:43:43 [7,634ms] [Error] [omni.kit.registry.nucleus.index_v2.index_sync] Syncing registry index failed for url: 'https://ovextensionsprod.blob.core.windows.net/exts/kit/prod/sdk/106.5/d02c707b/v2'. Exception: Failed to connect to the registry: 'https://ovextensionsprod.blob.core.windows.net/exts/kit/prod/sdk/106.5/d02c707b/v2'

Which results in:

2025-10-31 13:43:44 [8,834ms] [Error] [omni.kit.app.plugin] Exiting app because of dependency solver failure...
Error executing job with overrides: []
Traceback (most recent call last):
  File "/home/ealban/.cache/bazel/_bazel_ealban/23d0fc7ed1809e4449640aa464dcd946/execroot/_main/bazel-out/k8-fastbuild/bin/isaac/examples/spot_forward.runfiles/rules_python++pip+pypi_310_hydra_core/site-packages/hydra/_internal/instantiate/_instantiate2.py", line 92, in _call_target
    return _target_(*args, **kwargs)
  File "/home/ealban/.cache/bazel/_bazel_ealban/23d0fc7ed1809e4449640aa464dcd946/execroot/_main/bazel-out/k8-fastbuild/bin/isaac/examples/spot_forward.runfiles/_main/isaac/app.py", line 15, in __init__
    super().__init__(*args, **kwargs)
  File "/home/ealban/.cache/bazel/_bazel_ealban/23d0fc7ed1809e4449640aa464dcd946/execroot/_main/bazel-out/k8-fastbuild/bin/isaac/examples/spot_forward.runfiles/+_repo_rules+isaaclab/source/isaaclab/isaaclab/app/app_launcher.py", line 131, in __init__
    self._create_app()
  File "/home/ealban/.cache/bazel/_bazel_ealban/23d0fc7ed1809e4449640aa464dcd946/execroot/_main/bazel-out/k8-fastbuild/bin/isaac/examples/spot_forward.runfiles/+_repo_rules+isaaclab/source/isaaclab/isaaclab/app/app_launcher.py", line 781, in _create_app
    self._app = SimulationApp(self._sim_app_config, experience=self._sim_experience_file)
  File "/home/ealban/.cache/bazel/_bazel_ealban/23d0fc7ed1809e4449640aa464dcd946/external/+_repo_rules2+isaacsim/site-packages/isaacsim/exts/isaacsim.simulation_app/isaacsim/simulation_app/simulation_app.py", line 227, in __init__
    from .utils import create_new_stage, open_stage
  File "/home/ealban/.cache/bazel/_bazel_ealban/23d0fc7ed1809e4449640aa464dcd946/external/+_repo_rules2+isaacsim/site-packages/isaacsim/exts/isaacsim.simulation_app/isaacsim/simulation_app/utils.py", line 17, in <module>
    from omni.kit.usd import layers
ModuleNotFoundError: No module named 'omni.kit.usd'

Is https://ovextensionsprod.blob.core.windows.net/exts/kit/prod/106/shared/v2' down?

[Asgod-1]

same question

[Asgod-1]

have u solved it yet? i checked the two websites all 404. i persume they've been shut down cause the official documention says "Omniverse Launcher, Nucleus Workstation, and Nucleus Cache will be deprecated and will no longer be available starting October 1, 2025. Functionality may be reduced If these applications are used after this date."

[Shaw-Way]

I updated isaac lab to version 2.3.0, this issue never showed again.

[Asgod-1]

I updated isaac lab to version 2.2.0, this issue never showed again.

how u updated exactly?

[Shaw-Way]

how u updated exactly?

Using pip with following command. pip install isaaclab[isaacsim,all]==2.3.0 --extra-index-url https://pypi.nvidia.com