Why can't I install on my external ahrd drive?

[Ibn Mattuta]

Most games let me install on my normal hard drive or external, but for some reason Half life 2 and many other source games (counter strike 1.6, deathmatch classic, etc.) only let me install onto my internal SSD, which is full. Does anyone know why? (The hard drive is recognized, and I can install any other game on steam onto my external hard drive by clicking install and then opening the drop down menu and selecting it).

[Calmly Frenetic]

All games that share the same Source engine need to be installed on the same drive.
To get any on the external drive, you first need to uninstall ALL from the internal SSD.

http://steamcommunity.com/sharedfiles/filedetails/?id=208783207

After uninstalling all related games (including sourcemods and SDKs ?) you may also need to manually delete any folders that are left behind.
To avoid having to download everything again, use the Steam "Backup" feature or manually copy/move the folders.

[Ibn Mattuta]

Originally posted by Calmly Frenetic:

All games that share the same Source engine need to be installed on the same drive.
To get any on the external drive, you first need to uninstall ALL from the internal SSD.

http://steamcommunity.com/sharedfiles/filedetails/?id=208783207

After uninstalling all related games (including sourcemods and SDKs ?) you may also need to manually delete any folders that are left behind.
To avoid having to download everything again, use the Steam "Backup" feature or manually copy/move the folders.

Oh thanks, I'll just wait to play in until I get a new SSD

[GYMB4T]

Format it m8

[Naples]

format C:

[Jegahl]

The issue for me was Half-Life and Half-Life 2: Episode Two were still in my C drive's Steam folder even though Steam listed them as not installed. I'm not sure how that happened and I won't speculate. After deleting the folders manually I was able to install Half-Life to my D drive. Note I had already gone through the steps in the link Calmly Frenetic shared. They may have been blocking the installation as well. Thank you all for the informative thread.