Ask HTG: How Can I Reclaim The Full Capacity of an SD Card?

by Unknown at 7:35 AM

If you’ve used an SD card for more advanced purposes than simply storing digital photos (e.g. running a mobile or micro OS), you’ll find it requires a little more finesse than simply formatting the card to reclaim all the space. Read on as we show you how.

Dear How-To Geek,

I followed along with one of your great Raspberry Pi tutorials a few months ago. Just recently I upgraded to a bigger SD card for the Pi and pulled the old one to use for another project. When I went to reformat the card only 64MB out of the original capacity was available and even when I went into Disk Management in Windows the best I could do is dump the contents of the inaccessible (and presumably Linux-filled) partition. This left me with a tiny Windows accessible partition and a big phantom partition I can’t do anything with.

I’m sure there’s a simple fix but I’m not even sure if I did a good job describing my problem (so as you an imagine I’m at a loss for what to search for in Google to get to the bottom of things!) Help!

Sincerely,

Suffering from Stunted SD Card

Don’t worry Suffering, we grabbed a card we’d previously used for a Pi project just to recreate your situation and show you how to get the full capacity of your card back. The heart of the problem is the partition changes the SD card undergoes during the initial PI setup: 64MB of the card is reserved as a Windows-accessible FAT32 partition which hosts configuration files and other small files that benefit from cross-OS FAT32-based accessibility (so you can easily pop the SD card in a modern PC and tweak those configuration files) and the rest is formatted for use by Raspbian which is a Debian-derived version of Linux. As a result the majority of the card becomes somewhat of a black hole to Windows.

That said, it’s easy to repair when you have the right tool at your fingertips. First, let’s take a peek at what the SD card looks like if you attempt to reclaim the space using Disk Manager as you did: