How to: Reformat an SD card to get back all the space you lost when you screwed up making your Raspberry Pi RetroPie disk
Because I’m a good boy who must not be denied, I recently treated myself to a Raspberry Pi 4 with the idea of loading RetroPie on it and making myself a kick-ass gaming system circa 1994. Really, all I wanted to play was Intelligent Qube for the PS1, Populous from the Genesis, and Tetris and Dr. Mario from the SNES. Of course in the process I made a few mistakes, the worst of which was accidentally reformatting my 256GB Lacie Thunderbolt drive I use as a Cache drive for Adobe After Effects instead the 256 GB Samsung SD card I THOUGHT I was formatting. (Who knew Lacie used Samsung drives?) Anyway, the only advice I will offer to anyone else trying to make Retro Pi system is unplug ALL your peripherals first.
But so back to the point of this post. In successfully installing the software on the wrong drive, and then realizing my mistake, I then went to Disk Utility to attempt to reformat the drive back to it’s 256 GB of Mac OS Journaled goodness. However, when I examined the drive in Disk Utility, it only showed the drive having a capacity of 15 GB of FAT16 evilness. “That’s odd,” I thought, but I wasn’t worried because I figured if I just reformatted it, I would get all my disk space back. Nope. I instead got only 15GB of Mac OS Journaled goodness, but I did not get back my full 256 GB the drive should have had. So after spending WAY too long trying to figure out what was going on, as per usual, it was a stupidly simple thing I had over-looked/not realized changed at some point in Disk Utility.
You see this little drop down?
You want to make sure it is set to “Show all devices”, not just show all VOLUMES. If you have volumes only selected, then it only shows you actual disk volumes, like the 15 GB partition on my 256GB drive that had been formatted as a volume. Once that changed, I could then select the the ENTIRE drive correctly, and hit ERASE, thus reclaiming my entire 256 GB of Mac OS Journaled space.
I don’t know when that changed, or maybe I set it to show all devices 10 years ago and it kept that preference until some recent update, but in any event, that was the culprit. So if you ever have any trouble reformatting any hard drive or SD card on the Mac, be sure to check that drop down first and make sure you have the actual device selected, not just the volume/partition that the OS can see.
15GB?
Ahh. 256GB. Much better.
