I'm in desperate need to free up some disk space on my Macbook, so I went on Steam to delete a few of the heaviest games I haven't been playing.
Then I noticed something puzzling.
I had ~15GB free on my SSD when I went into my library and deleted CS:GO. According to Steam itself, CS:GO was roughly 8GB. I deleted it, by choosing "Delete Local Files". Having just deleted it, I checked and I now I have ~18GB free!
Steam told me CS:GO was using 8GB, but I only recovered about 3GB by deleting it.
How is this possible? Did I do something wrong? Are there "hidden files" or something similar that I can manually delete to free the remaining 5GB? Is it because CS:GO is a Source Engine game?
Before deleting CS:GO, I also deleted Borderlands 2 via the same method, and although I failed to specifically check how many free GBs I had before and after deletion, I'm confident that the same thing happened. I'm pretty sure I didn't get back the ~7GB it was using.
In essence, I'm worried that Steam is not freeing up space adequately when I delete my games. I'm thinking of deleting Steam as a whole, since I haven't been gaming all that much recently anyway. I wonder if that would fix this problem.
Best Answer
Ok, I found the answer, and it's a weird one.
Basically, it was Time Machine's fault.
I use TM as my backup mechanism, but I back my system to an external HD. So, I naturally assumed that my backups were all exclusively on that external HD.
Nope.
Time Machine takes liberties with the free space on your system partition. It uses as much free space as it thinks it can to store a local backup, known as "snapshots". It does this as a safety net measure, in case you need to back your system up and you don't have access to the external hard drive where the main backup is maintained.
What happened (I'm not 100% sure, but I think it's a good enough guess to personally accept it as an answer) is that, when I deleted large files such as Borderlands 2, CS:GO, and even iPhoto (good riddance), Time Machine saw more available space for its snapshots, and used it accordingly. As deleted from here, Time Machine used the space there.
And here was I, thinking my SSD was broken because it was reporting my free space wrong.
Anyway, how to "fix" it?
By disabling this weird and obscure (though possibly helpful) Time Machine behavior. This article explains it in detail, but basically you just type
sudo tmutil disablelocalinto the Terminal and approve the command using your system password. This disables the snapshots feature, and you're left with only the external HD backups — as I thought was the case all along. (And yes, the article says Mac OS X Lion, but it's the same on Mavericks or Yosemite.)That's it. I'm potentially less backed up now in case of an emergency, but now I have more available disk space than I know what to do with.
Guess I'm redownloading CS:GO...