Why can I only choose the drive I want to install my game onto for some games in Steam?

I have a 120GB SSD and a 2.0TB HDD. I love how steam has added the ability to specify where I can install my games. For most games when I go to install I get this option:

To which I can then select my HDD:

This works really well and I love it however for some games I simply get this:

I was just wondering if I could enable this lovely feature for ALL of my games or is this a bug or what?

Solution 1:

This is a limitation of steam's old game file content system. Only games on the new content system can be installed on different drives

Now, whenever you attempt to install a game using the new file system (pretty much anything recent, and many will update), when you choose to install you’ll have a dropdown box offering any of the folders you've set via the console option.

As developers update older games to the new content system this will become available. This feature seems to be about 2 months old.

There are some work arounds for this. You can use SteamTool Library Manager which makes use of NTFS Junctions.

You can also do something similar to what that tool does by creating symbol links. Guide for which can be found here.