I'm running PM 5.0, build 13444 (c5a5ad3), just installed today on a 27" core i5 2009 iMac running OS 10.8.2 with 8 GB of RAM.
I followed the instructions to install the context menu service application (BrowseWithPMService.Service version 1.0). Although "Open with PhotoMechanic" does appear in the right-click menu when I right-click on a folder and select the PM service, nothing else happens. PM 5 doesn't open that way.
While I had PM 4.6 on my system, the context menu successfully opened PM 4.6 but not 5.0. I then removed PM 4.6 from the system--thinking that it just confused the context menu service to have two versions of the main PM application on the same system--but that didn't improve the situation. PM 5 just won't open, although it will certainly open if I drop a folder on the icon of the application or double-click the applicatin directly.
I've tried moving BrowseWithPMService.Service into Services folders in the main Library, then into a Services folder in the System Library, and finally into a Services folder in my own user folder's Library. I've restarted each time I've made one of these changes, of course. Still doesn't work.
Any suggestions would be appreciated. Thanks in advance for whatever help you can provide.