Using the whole card: expanding the partition after writing a build

You wrote a 256GB build onto a 512GB card (good call, see why we go a size up), and now the build only shows 256GB of space. Where did the rest go? It is still there, just sitting as unallocated space: room on the card that no partition is using yet.

What is a partition?

A partition is a section of a drive with its own file system, a bit like rooms in a house. An image copies the builder’s rooms exactly, so if their card was 256GB, your rooms are 256GB too, and the rest of your card is an empty plot next door. Expanding just knocks through the wall so the last room uses the whole plot.

Honestly, if you are not adding your own games, you can ignore it. Nothing is lost and nothing is broken.

First: give it one boot

Some builds grow the partition by themselves the first time they start. Boot the build, let it get all the way to the menu, leave it a few minutes, then check the free space. See what to expect on first boot.

Batocera builds

Batocera keeps your games and saves on a big partition called SHARE (also called userdata). A fresh Batocera install grows SHARE to fill the card on its very first boot. A ready-made build has usually already been booted by the builder, so it often will not grow again on your card.

To check: on the main menu press Start, go to System Settings and look at the storage or free space figure. If it matches the build size rather than your card size, expand it:

1. Back up anything you care about (saves, settings). Resizing is usually safe, but a power cut mid-resize can ruin the partition.
2. Make a GParted Live USB stick on your PC (GParted is a free partition editor that boots on its own).
3. Boot a PC from that stick and plug in your build card or drive with a USB reader.
4. Pick the build card from the drop-down at the top right. Double-check it is the right one by its size.
5. Right-click the last, largest partition (SHARE), choose Resize/Move, drag it to fill the unallocated space, then click Apply.
6. Wait for it to finish, shut down, and put the card back in your device.

RetroPie builds

RetroPie runs on Raspberry Pi OS, which has a built-in expand option:

1. From the RetroPie menu, open raspi-config (it is in the RetroPie section of the main menu on most builds), or press F4 on a keyboard to get to a command line and type sudo raspi-config.
2. Go to Advanced Options, then Expand Filesystem.
3. Confirm, exit and reboot. The extra space appears after the restart.

RetroBat and other Windows builds

RetroBat is a folder on a normal Windows drive, so there is nothing to expand: it uses whatever space the drive has. If a Windows build came as a drive image and the drive shows less than it should:

1. Right-click Start and open Disk Management.
2. Find the drive. Unallocated space shows as a black bar.
3. Right-click the partition just to the left of it and choose Extend Volume, then follow the wizard.

Extend Volume only works if the unallocated space sits directly after the partition. If it is greyed out, GParted (above) can do it instead.

Other builds

Recalbox, handheld firmwares and others all handle this a bit differently, and some have their own expand option in the settings. Check the build’s post first, and the comments underneath, where someone has usually asked already.

Still stuck? See why an image will not fit and buying SD cards, or ask in our Discord.