# can not install Looking glass extension

**URL:** <https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665>\
**Category:** Support\
**Created:** [September 14, 2021, 12:58pm UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665 "2021-09-14T12:58:50Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![Donald\_Holm](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/donald_holm/32/12354_2.png) [@Donald\_Holm](https://discourse.slicer.org/u/Donald_Holm)\
**Post date:** [September 14, 2021, 12:58pm UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/1 "2021-09-14T12:58:50Z")

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I use Windows 10 with My Looking Glass. I’m following the install and use video. I’m at the point where I do a search for the Looking Glass extension but it does not show up. The page states it has 87. I look down I’m using the preview slicer per the video. Also when I close the Slicer I get an error about some CTKWidget.dll not found. I tried to install it twice.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 15, 2021, 1:29am UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/2 "2021-09-15T01:29:14Z")

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The SlicerLookingGlass extension is available for recent Slicer Preview Releases:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/e/5e89336393396f7f9bb6f27812eb856f85194ee7.jpeg)

Do you use the very latest Slicer Preview Release? If it does not show up, can you take a screenshot of your Extensions Manager after you type `look` in the searchbox?

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**Author:** ![Donald\_Holm](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/donald_holm/32/12354_2.png) [@Donald\_Holm](https://discourse.slicer.org/u/Donald_Holm)\
**Post date:** [September 15, 2021, 1:41am UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/3 "2021-09-15T01:41:27Z")

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Thanks, I must have had download problems this afternoon.

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**Author:** ![Donald\_Holm](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/donald_holm/32/12354_2.png) [@Donald\_Holm](https://discourse.slicer.org/u/Donald_Holm)\
**Post date:** [September 15, 2021, 2:02am UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/4 "2021-09-15T02:02:19Z")

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I download Slicer again. This time the Looking Glass icon does not show up. I can uninstall it so It must be there so what should I do?

 ![icon.png](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/6/9637e24be47d61acf9c1efae323babf65a0cf994.png)

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 15, 2021, 2:06am UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/5 "2021-09-15T02:06:18Z")

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You right-clicked on the toolbar area, so you can select there which toolbars are shown. Click on the search icon (magnifier glass) in the [module selection toolbar](https://slicer.readthedocs.io/en/latest/user_guide/user_interface.html#toolbar) to open a module.

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<div class="post-metadata">

**Author:** ![Donald\_Holm](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/donald_holm/32/12354_2.png) [@Donald\_Holm](https://discourse.slicer.org/u/Donald_Holm)\
**Post date:** [September 15, 2021, 2:36am UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/6 "2021-09-15T02:36:58Z")

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I’m getting there, Thanks for the help. The video is telling me to load the sample data. How do I get back to that screen from here? I do have it set to 3D only per the video.

 ![next.png](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/b/d/bd58f7e59da6d64d538f9110099f358402e00da0.png)

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<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 15, 2021, 3:11am UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/7 "2021-09-15T03:11:32Z")

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You can use the module selector to open the “Sample Data” module.

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<div class="post-metadata">

**Author:** ![Donald\_Holm](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/donald_holm/32/12354_2.png) [@Donald\_Holm](https://discourse.slicer.org/u/Donald_Holm)\
**Post date:** [September 15, 2021, 3:23pm UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/8 "2021-09-15T15:23:43Z")

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![error.png](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/2/323bbbd8c0a0e7dd8c77514729b2c40702082fe6.png)The video wants me to load the CTA but I get this error. I’m I missing something? What other samples can I try and what would be the volume settings?

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<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 15, 2021, 4:35pm UTC](https://discourse.slicer.org/t/can-not-install-looking-glass-extension/19665/9 "2021-09-15T16:35:25Z")

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Maybe download fails because you are behind a corporate/hospital firewall. You can download the file angio CT dataset using [this link](https://slicer-packages.kitware.com/api/v1/item/61267e0b342a877cb3b8f5cc/download) and drag-and-drop the file to the Slicer window to load it.