# VMTK not found after download

**URL:** <https://discourse.slicer.org/t/vmtk-not-found-after-download/18661>\
**Category:** Support\
**Tags:** vmtk\
**Created:** [July 13, 2021, 8:45am UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661 "2021-07-13T08:45:05Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![AshvinGupta](https://avatars.discourse-cdn.com/v4/letter/a/4af34b/32.png) [@AshvinGupta](https://discourse.slicer.org/u/AshvinGupta)\
**Post date:** [July 13, 2021, 8:45am UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661/1 "2021-07-13T08:45:05Z")

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Hello! After downloading the new preview version of Slicer every time I try to use the VMTK extension I get the same error message: “VMTK library is not found.” This is quite odd as when I go to extensions manager, it says that SlicerVMTK is installed.  
Also if I try to access the older version of slicer and download VMTK I get the error seen below or then when I do mange to download it, “VMTK library is not found.” Any help on this would be greatly appreciated.

 ![Screenshot 2021-07-13 at 10.08.20](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/c/6/c61dc55dd1a97d92b6bff6f4e21d2156dd23c1b2.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:** [July 13, 2021, 3:14pm UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661/2 "2021-07-13T15:14:32Z")

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VMTK is available for latest Slicer Stable Release and latest Slicer Preview Release. The errors that you show in the screenshot above are due to instability of the extension server. The server will be replaced later this week, until then a workaround is to retry a few hours later.

If you installed the VMTK extension but modules do not show up or work properly then please upload the application log (menu: Help / Report a bug) somewhere and post the download link here so that we can investigate.

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<div class="post-metadata">

**Author:** ![AshvinGupta](https://avatars.discourse-cdn.com/v4/letter/a/4af34b/32.png) [@AshvinGupta](https://discourse.slicer.org/u/AshvinGupta)\
**Post date:** [July 14, 2021, 9:01am UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661/4 "2021-07-14T09:01:26Z")

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[VMTK bug](https://drive.google.com/file/d/1SAK6LiwYOtzvqS6BPxAvlM_grkpJraqo/view?usp=sharing)

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<div class="post-metadata">

**Author:** ![AshvinGupta](https://avatars.discourse-cdn.com/v4/letter/a/4af34b/32.png) [@AshvinGupta](https://discourse.slicer.org/u/AshvinGupta)\
**Post date:** [July 23, 2021, 1:39pm UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661/5 "2021-07-23T13:39:33Z")

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Has there been any update on this? I tried downloading the latest version and trying again but get the following error messages:  
[DEBUG][Qt] 23.07.2021 14:31:18 [] (unknown:0) - Additional module paths …: Extensions-30058/SlicerVMTK/lib/Slicer-4.13/qt-loadable-modules, Extensions-30058/SlicerVMTK/lib/Slicer-4.13/qt-scripted-modules  
[CRITICAL][Qt] 23.07.2021 14:31:19 [] (unknown:0) - Error(s):  
CLI executable: /Applications/Slicer.app/Contents/Extensions-30058/SlicerVMTK/lib/Slicer-4.13/qt-loadable-modules/vtkvmtk.py  
The process failed to start. Either the invoked program is missing, or you may have insufficient permissions to invoke the program.  
[CRITICAL][Qt] 23.07.2021 14:31:19 [] (unknown:0) - Fail to instantiate module “vtkvmtk”  
[CRITICAL][Qt] 23.07.2021 14:31:19 [] (unknown:0) - The following modules failed to be instantiated:  
[CRITICAL][Qt] 23.07.2021 14:31:19 [] (unknown:0) - vtkvmtk  
[DEBUG][Python] 23.07.2021 14:31:20 [Python] (/Applications/Slicer.app/Contents/lib/Slicer-4.13/qt-scripted-modules/SubjectHierarchyPlugins/AbstractScriptedSubjectHierarchyPlugin.py:36) - Scripted subject hierarchy plugin registered: Annotations

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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:** [August 9, 2021, 7:15pm UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661/6 "2021-08-09T19:15:35Z")

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Thank you for your patience. You can use VMTK on other platforms (Windows/Linux) and we’ll fix it in the latest Slicer Stable Release, too - see progress here:

> <https://github.com/vmtk/SlicerExtension-VMTK/issues/37>
>
> The extension installation package does not contain VMTK binaries, only the Slic…er module .py files.
> 
> It seems that the recent upgrade to VTK9 broke packaging for VTK-8.2.

@jcfr

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<div class="post-metadata">

**Author:** ![AmandineG](https://avatars.discourse-cdn.com/v4/letter/a/8edcca/32.png) [@AmandineG](https://discourse.slicer.org/u/AmandineG)\
**Post date:** [February 20, 2023, 1:53pm UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661/7 "2023-02-20T13:53:22Z")

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Hi!

I have this error message today :  
[Qt] Error(s):  
[Qt] CLI executable: /Applications/Slicer.app/Contents/Extensions-31317/SlicerVMTK/lib/Slicer-5.2/qt-loadable-modules/vtkvmtk.py  
[Qt] The process failed to start. Either the invoked program is missing, or you may have insufficient permissions to invoke the program.  
[Qt] Fail to instantiate module “vtkvmtk”  
[Qt] The following modules failed to be instantiated:  
[Qt] vtkvmtk

This extension worked very well until now.  
I have the latest Slicer Stable Release.  
I have uninstalled and reinstalled the extension with restarts of 3D slicer but the same error message remains.

How can I get it to work again without error?

Thanks

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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:** [March 2, 2023, 6:28am UTC](https://discourse.slicer.org/t/vmtk-not-found-after-download/18661/8 "2023-03-02T06:28:58Z")

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> [@AmandineG](#):
>
> The process failed to start. Either the invoked program is missing, or you may have insufficient permissions to invoke the program.

This is a false alarm, you can safely ignore it. See more details [here](https://github.com/vmtk/SlicerExtension-VMTK/issues/22).

Do you find any issues when you are using VMTK in Slicer?