# Avogadro2 1.100 not finding OpenBabel

**URL:** <https://discuss.avogadro.cc/t/avogadro2-1-100-not-finding-openbabel/7060>\
**Category:** Support\
**Created:** [July 23, 2025, 6:56pm UTC](https://discuss.avogadro.cc/t/avogadro2-1-100-not-finding-openbabel/7060 "2025-07-23T18:56:54Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![GeorgeSR](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/georgesr/32/2917_2.png) [@GeorgeSR](https://discuss.avogadro.cc/u/GeorgeSR)\
**Post date:** [July 23, 2025, 6:56pm UTC](https://discuss.avogadro.cc/t/avogadro2-1-100-not-finding-openbabel/7060/1 "2025-07-23T18:56:55Z")

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Hi, I’m trying to optimize geometry in Avogadro 1.100, but to no avail. Hoping someone here can help me find where I went wrong.

## Environment Information

Avogadro version: 1.100  
Operating system and version: Windows 11 Enterprise, 24H2

## Expected Behavior

- Draw simple unoptimized molecule, e.g. methane with an H dragged far away
- Extensions → Optimize Geometry
- Geometry of molecule optimized, e.g. methane goes back to normal bond lengths and tetrahedral geometry

## Actual Behavior

- Draw simple unoptimized molecule, e.g. methane with an H dragged far away
- Extensions → Optimize Geometry
- Small pop-up briefly appears with an “Optimize Geometry” loading bar at 0%, then disappears
- Molecule geometry remains unoptimized
- Log file (uploaded below) indicates that OpenBabel is not found, and all entries in the sub-menu Extensions → Open Babel are grayed out

> Warning: “obabel.exe not found! Disabling Open Babel plugin actions.” (:0, )

## Things I’ve Checked

- Installed the current official release of Avogadro 1.100 for Windows from [here](https://two.avogadro.cc/install/index.html) (while writing this post, I noticed the Windows release I used is no longer available due to a bug. Not sure if that’s related, but I haven’t tried the Nightly Build yet.)
- Python is installed, Extensions → Python Settings shows correct environment (3.12.7)
- 64-bit version of OpenBabel installed in default directory (C:\Program Files\OpenBabel-3.1.1). Do I need to add Open Babel directory to Path?

Thanks!

[avogadro2.log](https://discuss.avogadro.cc/uploads/short-url/pEy9gEOkPCLre8M1NAyPDEsLO6D.log) (4.7 KB)

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<div class="post-metadata">

**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\
**Post date:** [July 23, 2025, 7:37pm UTC](https://discuss.avogadro.cc/t/avogadro2-1-100-not-finding-openbabel/7060/2 "2025-07-23T19:37:50Z")

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Yep. Try a nightly build:

> **[Install — Avogadro 1.100.0 documentation](https://two.avogadro.cc/install/)**

I don’t exactly know what happened with the 1.100 release on Windows, but I’m working to fix it for 1.101 later this summer.

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<div class="post-metadata">

**Author:** ![GeorgeSR](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/georgesr/32/2917_2.png) [@GeorgeSR](https://discuss.avogadro.cc/u/GeorgeSR)\
**Post date:** [July 24, 2025, 6:31pm UTC](https://discuss.avogadro.cc/t/avogadro2-1-100-not-finding-openbabel/7060/3 "2025-07-24T18:31:47Z")

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Seems to be working fine after adding C:\Program Files\OpenBabel-3.1.1 to Path.

I did subsequently switch to the nightly build as recommended.

Thanks for the help and looking forward to 1.101!

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**Author:** ![system](https://discuss.avogadro.cc/uploads/default/original/1X/93fe5a56d10b304e678127e54139c28cde211662.png) [@system](https://discuss.avogadro.cc/u/system)\
**Post date:** [July 27, 2025, 6:32pm UTC](https://discuss.avogadro.cc/t/avogadro2-1-100-not-finding-openbabel/7060/4 "2025-07-27T18:32:12Z")

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