Hi Matthias, As I understand it, that is a "feature" of the Mac OS (not due to ChimeraX) that it treats differently capitalized directory and file names as the same as each other. I.e. it is case-insensitive. For example, on the Mac, "cd ~/Desktop" and "cd ~/desktop" go to the same place. Searching the web suggests there are ways to change your Mac system from case-insensitive (default) to case-sensitive (what you want), but they did not look simple to me. I can't vouch for whether it's accurate, but here is one link I found: <https://docs.spryker.com/docs/scos/dev/tutorials-and-howtos/howtos/howto-handle-case-sensitive-file-system-on-mac-os.html> Best, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Aug 14, 2023, at 7:10 AM, Vorländer,Matthias Kopano via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:

Dear Developers,

I have found a strange behavior when saving files through the chimeraX command line. Essentially, file naming does not seem to be properly sensitive to capitalization. For example, when I am trying to save a file called “chain_A.pdb” and then another file called “chain_a.pdb”, “chain_A.pdb” will be overwritten with the contents of “chain_a.pdb”. It also does not matter if I am saving a pdb file or a log file. If “chain_A.pdb” does not exist, then “chain_a.pdb” will be correctly saved with as a lowercase a.

Details: version 1.6.1 (2023-05-09) OS: MacOS Catalina Version 10.15.7

Would be great if this could be fixed : ) Many thanks in advance, Matthias