# Cannot install any extension updates

**URL:** <https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912>\
**Category:** Support\
**Tags:** extensions-manager\
**Created:** [August 17, 2026, 11:03pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912 "2026-08-17T23:03:05Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![RushAR3DLab](https://avatars.discourse-cdn.com/v4/letter/r/8491ac/32.png) [@RushAR3DLab](https://discourse.slicer.org/u/RushAR3DLab)\
**Post date:** [August 17, 2026, 11:03pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/1 "2026-08-17T23:03:05Z")

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hi, I upgraded today from 3d Slicer v 5.8 to 5.12 (latest stable version), because I had been experiencing the same issue already with v 5.8. When I launch Extension Manager it cannot download the files for updates. The python console shows this:

> [Qt] An OpenGL Core Profile was requested, but it is not supported on the current platform. Falling back to a non-Core profile. Note that this might cause rendering issues.
> 
> [Qt] A cookie associated with a cross-site resource at [http://www.nitrc.org/](http://www.nitrc.org/) was set without the `SameSite` attribute. A future release of Chrome will only deliver cookies with cross-site requests if they are set with `SameSite=None` and `Secure`. You can review cookies in developer tools under Application\>Storage\>Cookies and see more details at [Chrome Platform Status](https://www.chromestatus.com/feature/5088147346030592) and [Chrome Platform Status](https://www.chromestatus.com/feature/5633521622188032) .
> 
> [Qt] Failed downloading: [https://slicer-packages.kitware.com/api/v1/file/6a709511e5707846f0878d73/download](https://slicer-packages.kitware.com/api/v1/file/6a709511e5707846f0878d73/download)

On top of that, it will only get to the Extension Manager if it does not freeze upon start up. I am running this version from a Win 11, Intel Core Ultra 7 255HX (2.40 GHz), w 64 GB RAM HP laptop.

Still a newbie on this, so any help is appreciated. When I first installed v 5.8, the extension manager worked seamlessly on this same laptop. Can it be something in my network? BTW this happens on two different Win 11 PCs.

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**Author:** ![ebrahim](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ebrahim/32/13403_2.png) [@ebrahim](https://discourse.slicer.org/u/ebrahim)\
**Post date:** [August 18, 2026, 12:24pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/2 "2026-08-18T12:24:51Z")

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From your network are you able to download the package directly from the URL in your error message? [https://slicer-packages.kitware.com/api/v1/file/6a709511e5707846f0878d73/download](https://slicer-packages.kitware.com/api/v1/file/6a709511e5707846f0878d73/download)

Just to test first whether it’s a network access problem or somehting else

(as for the extension manager sometimes freezing up on windows maybe some others can reply if they have encountered this)

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**Author:** ![RushAR3DLab](https://avatars.discourse-cdn.com/v4/letter/r/8491ac/32.png) [@RushAR3DLab](https://discourse.slicer.org/u/RushAR3DLab)\
**Post date:** [August 18, 2026, 6:15pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/3 "2026-08-18T18:15:17Z")

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thanks for the suggestion. I was able to download manually, so that possibly discards the network theory. Since I have that file, I should be able to install manually as well, right?

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**Author:** ![ebrahim](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ebrahim/32/13403_2.png) [@ebrahim](https://discourse.slicer.org/u/ebrahim)\
**Post date:** [August 18, 2026, 7:00pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/4 "2026-08-18T19:00:07Z")

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Yes you can install the package manually using the “install from file” button (like shown [here](https://slicer.readthedocs.io/en/latest/user_guide/extensions.html#install-extensions))

(But the extension manager should work 🫤)

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**Author:** ![enjy\_sallam](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/enjy_sallam/32/82679_2.png) [@enjy\_sallam](https://discourse.slicer.org/u/enjy_sallam)\
**Post date:** [August 19, 2026, 4:52am UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/5 "2026-08-19T04:52:41Z")

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the extension manager site is not loading

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**Author:** ![ebrahim](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ebrahim/32/13403_2.png) [@ebrahim](https://discourse.slicer.org/u/ebrahim)\
**Post date:** [August 19, 2026, 1:07pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/6 "2026-08-19T13:07:40Z")

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You can check in your browser whether the site loads: [https://extensions.slicer.org/](https://extensions.slicer.org/)

It does seem to be up

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**Author:** ![RushAR3DLab](https://avatars.discourse-cdn.com/v4/letter/r/8491ac/32.png) [@RushAR3DLab](https://discourse.slicer.org/u/RushAR3DLab)\
**Post date:** [August 19, 2026, 6:18pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/7 "2026-08-19T18:18:13Z")

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Hit or miss results so far. In 5.12 I am able to download and install as described, extensions manager is reachable, but in 5.8, when trying this method to update some extensions it says that they are already installed so it is skipping it. Maybe time to upgrade to 5.12 anyway, for example MuscleMap is not available from 5.8 but I was able to install it for 5.12.

I think that this manual mode is working so far, so I guess we can close this thread for the time being. Thanks to all who replied.

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**Author:** ![jamesobutler](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jamesobutler/32/7511_2.png) [@jamesobutler](https://discourse.slicer.org/u/jamesobutler)\
**Post date:** [August 19, 2026, 7:06pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/8 "2026-08-19T19:06:53Z")

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@RushAR3DLab are you using a personal computer or one provided and configured by a corporate enterprise? Generally we find this inability to directly install using the Extension Manager when Zscaler or other similar software (e.g. Cisco Secure Access) is installed as it interrupts the connection to the Slicer extensions server resulting in failed downloads.

For example I can only install extensions by manually downloading and installing from file myself and which is an annoying situation I have dealt with for awhile.

cc @Sam_Horvath @lassoan @pieper as a possible topic regarding Slicer’s future in respect to a possible new solution for extension distribution being easier and not getting blocked by these zero trust corporate policies applied to many user’s computers.

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<div class="post-metadata">

**Author:** ![RushAR3DLab](https://avatars.discourse-cdn.com/v4/letter/r/8491ac/32.png) [@RushAR3DLab](https://discourse.slicer.org/u/RushAR3DLab)\
**Post date:** [August 19, 2026, 7:13pm UTC](https://discourse.slicer.org/t/cannot-install-any-extension-updates/47912/9 "2026-08-19T19:13:39Z")

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hi James

important point. These are, in fact, institutionally owned PCs with a corporate enterprise image. There are probably a few of those that you mention working behind scenes in our case.

Alejandro