How to prevent Yosemite's Finder from seeing a folder with a .epub extension as a epub file? This is a problem new to Yosemite. I have a folder called "com.acme.epub". The Finder sees this as an ePub file and won't let me access it as a folder. I can access it as a directory via the Terminal but if I do "open .", then it launches iBooks (which is not my default epub application). How do I get the Finder to see this folder as an actual folder/directory and not as an epub file? Note: Renaming the folder is not an option.

This same behavior occurs with folders that end with a ".key" string; it probably happens with certain other strings as well.

I am using OS X 10.10.3. This problem did not occur in 10.9 or 10.8.
You could look at using duti, a command line tool that lets you change the the file type association of an extension.

Along with duti, something like this could work:

com.apple.finder    .epub
com.apple.finder    .key
com.apple.finder    .numbers