# 'openmc' returned non-zero exit status 255 **URL:** \ **Category:** User Support\ **Created:** [November 3, 2020, 3:24pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844 "2020-11-03T15:24:13Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 3:24pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/1 "2020-11-03T15:24:13Z")
Dear All, I am new to OpenMC and just trying to repeat the example model of criticality search on my own laptop. But it showed the error with Command ‘openmc’ returned non-zero exit status 255. I downloaded OpenMC using Anaconda. Does anyone knows how to solve it? thx Yibo ![image](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/d/d7e3a743817b9ba35b16e00b132e4e8648bb643e.png) ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 3:27pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/2 "2020-11-03T15:27:30Z")
![1481604417152_.pic_hd](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/e/e3ce453157728bec02781bbb8ed18a4db03729cc.jpeg) Here is a more clear picture of the error dercription. ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [November 3, 2020, 4:24pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/3 "2020-11-03T16:24:21Z")
@Yibo Welcome to the forum. Did you try restarting the `Jupiter kernel`? I would say to restart your kernel and run the notebook again. ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 4:30pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/5 "2020-11-03T16:30:53Z")
Yes I tried “restart and run all” in the command but it still shows the error. ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [November 3, 2020, 5:12pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/6 "2020-11-03T17:12:47Z")
@Yibo, Can you share your Notebook script? ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 5:29pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/7 "2020-11-03T17:29:25Z")
It said that new users can not attached file so i can only share you the picture. It’s actually the example of Criticality research on this page:[https://docs.openmc.org/en/stable/examples/search.html](https://docs.openmc.org/en/stable/examples/search.html) ![example1](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/3/3ab1d0f95b26d5597d0ff62f665af7c2a55ce8c3.jpeg) ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 5:30pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/8 "2020-11-03T17:30:17Z")
And here is the left part. ![example2](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/c/c59ab68a7a15a10819ab103fbb51025d1973e462.jpeg) ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [November 3, 2020, 5:54pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/9 "2020-11-03T17:54:55Z")
@Yibo I didn’t face any error and I am not sure why are you seeing `‘openmc’ returned non-zero exit status 255` error? Did you try installing OpenMC again on a new conda environment? ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 6:04pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/10 "2020-11-03T18:04:20Z")
Yeah I have tried several times. I download OpenMC using the “conda create -n openmc-env openmc” code and the version of my OpenMC is 0.12.0 with Python 3.7.1. ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 6:16pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/11 "2020-11-03T18:16:03Z")
And i just delete my original environment and install it again with now python 3.9 but it still shows the same error. ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [November 3, 2020, 6:53pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/12 "2020-11-03T18:53:16Z")
@Yibo, Still now didn’t see any error with python 3.7 and 3.9. Other’s can give a better answer. ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 3, 2020, 7:39pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/13 "2020-11-03T19:39:55Z")
I tried re-download all the thing form anaconda but it still do not work. Still thank you for your help Pranto! ---
**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\ **Post date:** [November 4, 2020, 5:56pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/14 "2020-11-04T17:56:32Z")
@Yibo When you run `openmc.run`, under the hood the `openmc` executable is called. You should see output from the executable on the terminal associated with your Jupyter notebook. If you don’t see it, I would go to the directory with the .xml files that were generated using a terminal and run `openmc`. This should give you more information about what is going wrong. ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 4, 2020, 7:53pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/15 "2020-11-04T19:53:30Z")
Thank you for your help! When I run openmc.run it shows an error that “HDF5 data format uses version 1.0 whereas my installation of OpenMC expects version 3.x data.” How could I get that version of data? ---
**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\ **Post date:** [November 4, 2020, 8:04pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/16 "2020-11-04T20:04:43Z")
Pregenerated HDF5 libraries can be found at [https://openmc.org/](https://openmc.org/) ---
**Author:** ![Yibo](https://avatars.discourse-cdn.com/v4/letter/y/d26b3c/32.png) [@Yibo](https://openmc.discourse.group/u/Yibo)\ **Post date:** [November 4, 2020, 9:04pm UTC](https://openmc.discourse.group/t/openmc-returned-non-zero-exit-status-255/844/17 "2020-11-04T21:04:01Z")
Thank you Paul! It works finally.