# NIfTI (.nii.gz) loading failure for TotalSegmentator samples in 3D Slicer 5.10.0 on Apple M4 Pro

**URL:** <https://discourse.slicer.org/t/nifti-nii-gz-loading-failure-for-totalsegmentator-samples-in-3d-slicer-5-10-0-on-apple-m4-pro/47405>\
**Category:** Support\
**Created:** [June 20, 2026, 9:39pm UTC](https://discourse.slicer.org/t/nifti-nii-gz-loading-failure-for-totalsegmentator-samples-in-3d-slicer-5-10-0-on-apple-m4-pro/47405 "2026-06-20T21:39:13Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![khorlint](https://avatars.discourse-cdn.com/v4/letter/k/59ef9b/32.png) [@khorlint](https://discourse.slicer.org/u/khorlint)\
**Post date:** [June 20, 2026, 9:39pm UTC](https://discourse.slicer.org/t/nifti-nii-gz-loading-failure-for-totalsegmentator-samples-in-3d-slicer-5-10-0-on-apple-m4-pro/47405/1 "2026-06-20T21:39:13Z")

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**Description:**

I am encountering a consistent error when loading multiple samples from the TotalSegmentator dataset in 3D Slicer (version 5.10.0) on an Apple M4 Pro machine.

**Environment:**

- 3D Slicer version: 5.10.0
- OS: macOS (Apple Silicon M4 Pro)
- Dataset: TotalSegmentator v201
- File format: `.nii.gz` (NIfTI compressed)

**Issue:**

When attempting to load CT volumes (e.g. `s0000/ct.nii.gz`), 3D Slicer fails to load the file. This issue is not consistent across the dataset, as other samples load correctly.

**Error message:**

```auto
Error occurred while loading the selected files.
Click 'Show details' button and check the application log for more information.
Error: Loading /Users/<user>/Documents/Datasets/Totalsegmentator_dataset_v201/s0000/ct.nii.gz - load failed.

```

**Behavior:**

- The same error occurs across multiple samples, not limited to `s0000`
- No additional information is shown in the UI beyond the generic load failure
- File paths and dataset structure are correct

**Expected behavior:**

The `.nii.gz` CT volumes should load normally into Slicer as volumetric data.

**Request:**

Any insights into:

- Potential incompatibility with Apple Silicon (M4 Pro) builds
- Known issues with `.nii.gz` loading in Slicer 5.10.0
- Required configuration, plugins, or ITK settings
- Possible workaround or diagnostic steps

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**Author:** ![ThomasVanParys](https://avatars.discourse-cdn.com/v4/letter/t/7ea924/32.png) [@ThomasVanParys](https://discourse.slicer.org/u/ThomasVanParys)\
**Post date:** [June 21, 2026, 3:36pm UTC](https://discourse.slicer.org/t/nifti-nii-gz-loading-failure-for-totalsegmentator-samples-in-3d-slicer-5-10-0-on-apple-m4-pro/47405/2 "2026-06-21T15:36:45Z")

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I have only managed to succesfully import volumes as NIFTI or NRRD if they are ‘uncompressed’ and saved as a ‘float’ file via the CAST SCALAR VOLUME module. This goes for StradView and Avizo too. If the file is compressed, it usually doesn’t import the full image sequence/volume…

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**Author:** ![drnoorfatima](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/drnoorfatima/32/81980_2.png) [@drnoorfatima](https://discourse.slicer.org/u/drnoorfatima)\
**Post date:** [June 22, 2026, 3:18pm UTC](https://discourse.slicer.org/t/nifti-nii-gz-loading-failure-for-totalsegmentator-samples-in-3d-slicer-5-10-0-on-apple-m4-pro/47405/3 "2026-06-22T15:18:29Z")

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**Hi Khorlint,**

This is a known issue tied to the ITK NIfTI streaming reader crashing during block decompression of heavily compressed `.nii.gz` files on Apple Silicon (M4/M3 architectures) in Slicer 5.10. Try using python force loader, bypassing the UI reader.as slicers default loader uses general reader.