In Pre-Yosemite, I had some finder menu services (i.e. Right-Click, see 'Services' in menu, hover over, and you'd see Services created in Automator) that I made. As a developer, these were very handy as I'd often have to rename a large amount of files to some criteria (i.e. removing/replacing/adding text). I can make services fine now, and even get them to work within Automator (dragging and dropping the file(s) into Automator). However, if I right-click the file(s), hover over 'Service' and select my service, it never runs. In fact, if I check Activity Monitor, I see 'Automator Runner' just hanging there (one for each time I try). I have tried restarting and logging out and in. This doesn't fix it.
Note: I am running OS X Yosemite.
Best Answer
Open and re-save your services in Automator.
This will update them to work with Yosemite, and also warn you of any incompatibilities with the actions you're using in the services.
As a side note, this definitely should be something you're notified about when trying to run an old service, but at least you don't need to re-create new duplicate services.