# Problem with key(?)

**URL:** <https://opendata-forum.cern.ch/t/problem-with-key/559>\
**Category:** CMS\
**Created:** [5 June 2026 20:40 UTC](https://opendata-forum.cern.ch/t/problem-with-key/559 "2026-06-05T20:40:40Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![harr](https://opendata-forum.cern.ch/letter_avatar_proxy/v4/letter/h/a88e57/32.png) [@harr](https://opendata-forum.cern.ch/u/harr)\
**Post date:** [5 June 2026 20:40 UTC](https://opendata-forum.cern.ch/t/problem-with-key/559/1 "2026-06-05T20:40:40Z")

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My students are having a problem when trying to access the DoubleParked\_Muons data, stopping while trying to access a private key. Do you have any suggestions?

Thanks\>

> When attempting to run the dimuon spectrum analysis code on the 2016 proton-proton CMS open data docker container. When compiling a script using root, this error message popped up.
> 
> 260603 19:43:09 246 secgsi\_InitProxy: cannot access private key file: /home/cmsusr/.globus/userkey.pem
> 
> The file that was being accessed via this line in the script
> 
> ROOT::RDataFrame df(“Events”, “root://eospublic.cern.ch//eos/opendata/cms/derived-data/AOD2NanoAODOutreachTool/Run2012BC\_DoubleMuParked\_Muons.root”);
> 
> The code came from the .C file in this github project [https://github.com/cms-opendata-analyses/DimuonSpectrumNanoAODOutreachAnalysis](https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fcms-opendata-analyses%2FDimuonSpectrumNanoAODOutreachAnalysis&data=05%7C02%7Crobert.harr%40wayne.edu%7C53149420d2b74db7407008dec19f9b7b%7Ce51cdec9811d471dbbe6dd3d8d54c28b%7C1%7C0%7C639161088402460861%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=iEvXbYz2uKT50RkCsD%2FckPRnVZUw%2FsmCaS9kD4Zalyo%3D&reserved=0)

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**Author:** ![jmhogan](https://opendata-forum.cern.ch/letter_avatar_proxy/v4/letter/j/779978/32.png) [@jmhogan](https://opendata-forum.cern.ch/u/jmhogan)\
**Post date:** [8 June 2026 08:56 UTC](https://opendata-forum.cern.ch/t/problem-with-key/559/2 "2026-06-08T08:56:12Z")

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Hi Rob,

Just letting you know I’m checking into this. I can see that the file is accessible to me on a cluster with ROOT, e.g. just running `root root://eospublic.cern.ch//eos…`to open the file. It might be helpful to know if you see the same error when doing a typical file open like that in ROOT as opposed to dataframe command.

Thanks,

Julie Hogan