Can I buy DLC for a game I don't have installed?

Lets say I got a game in my Steam library but I don't have it installed. Can I still buy DLC for it, though?

For example, I have Empire: Total War, but I don't have it installed. Now, I'd like to buy a unit pack since it's on sale as part of Steam Summer Sales. Considering I don't actually have the base game installed, would it work?

Solution 1:

Yes, you can buy the DLC on the Steam store. All you need is a paid copy of the game in your library. You don't need to have it installed to buy it.

The message reads as follows:

Requires the base game {game} on Steam in order to play.

This is meant to inform you that you have no use for the DLC - and indeed, cannot buy it - if you do not own the base game on Steam. This is to prevent you from snatching timed free DLC, for instance - and to prevent complaints, obviously.

The DLC will also be automatically installed alongside the game when you download it via Steam - excluding some instances where the DLC actually includes a standalone executable.

If you attempt to buy DLC for a game you don't own on Steam, Steam will tell you - after choosing "purchase for myself" - the following:

Your transaction failed because you are trying to buy '{DLC}' which requires ownership of '{game}'. Please correct the error and try again.