Oh dear. Sorry Ute, I'm afraid that I miss-read your original email.  I was using the command open:ccd pim, which, I've just realised, you said worked.  Sorry for the confusion.  Out of interest where did you download the PIM.cif file and I will try opening it in the GUI.

TobyS
From: Ute Roehrig <Ute.Roehrig@sib.swiss>
Sent: 24 November 2025 10:30
To: Starborg, Toby (RFI,RAL,BPSUP) <tobias.starborg@rfi.ac.uk>
Subject: Re: Problem opening local small-molecule CIF file
 
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Hi Toby,

Which command is working for you?

"open PIM.cif" does not work for me on linux/version 1.11.dev2025*,  linux/version 1.10, macOS Tahoe/version 1.11.dev2025*,  macOS Tahoe/version 1.10.1

Thanks,
Ute

From: Starborg, Toby (RFI,RAL,BPSUP) <tobias.starborg@rfi.ac.uk>
Sent: Monday, November 24, 2025 10:56
To: Mailing List <chimerax-users@cgl.ucsf.edu>; Ute Roehrig <Ute.Roehrig@sib.swiss>
Subject: Re: Problem opening local small-molecule CIF file
 
Hi Ute,  I'm by no means an expert, but I just tried the same command and it worked fine for me.  Perhaps you need to expand the info to include what version of ChimeraX you are using and on what system? [FYI, I'm using version 1.10 on a Macbook Pro running Sequoia 15.7.1).

TobyS
From: Ute Roehrig via ChimeraX-users <chimerax-users@cgl.ucsf.edu>
Sent: 24 November 2025 09:49
To: Mailing List <chimerax-users@cgl.ucsf.edu>
Subject: [chimerax-users] Problem opening local small-molecule CIF file
 
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Hello,

I'm having problems opening a locally stored small-molecule cif file.

For example, the following runs without problems:
open ccd:pim

But if I download the file (PIM.cif) and try to open it with ChimeraX, I get an error:
open PIM.cif -> No mmCIF models found.
open PIM.cif format corecif -> No small molecule CIF models found. Perhaps this is a mmCIF file?
open PIM.cif format smallcif -> No small molecule CIF models found. Perhaps this is a mmCIF file?

Thank you in advance for your help,
Ute