Hi Oliver, In my tests with the current daily build, I don’t have this problem (double-clicking PDB file in Finder opens it in the currently running Chimera). However, I do remember a problem with Mac OS that if you have more than one Chimera copy installed, it stubbornly insists on sending the file to one of those even if you repeatedly designate opening in a different Chimera. Could this be the problem? If it’s starting another instance of the same copy/version of Chimera that you already have running (or you only have one version of Chimera on your computer), however, I don’t know what the issue might be. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Jan 27, 2018, at 9:25 AM, Oliver Clarke <olibclarke@gmail.com> wrote:

Hi, I have Chimera listed as the default app on my Mac to open MRC and PDB files. It used to be that if I double clicked on a pdb, and I had Chimera open, the pdb would open in that instance of chimera. Now, it always spawns a new instance of chimera. Is there any way to revert to the old behavior? Cheers Oli