I installed Linux Mint Cinnamon alongside Windows on an older Dell Inspiron 14-3467 using UEFI, but Mint's file manager reports that only about 1.7 GB is available. I'd like Mint to become my primary operating system because Windows runs poorly on this laptop. How can I determine which partitions belong to Windows, Mint, and the EFI system, then safely give Mint more of the drive? Windows appears to use /dev/sda1, while /dev/sda3 occupies much of the disk. What is /dev/sda3, and is it safe to remove or resize? I don't remember exactly which partitions I created for Mint, so I'd also appreciate commands or tools for identifying them.
4 Answers
The reported 1.7 GB may be free space on Mint’s root filesystem rather than free space on the whole disk. Run `df -h` to confirm which mounted filesystem is full. If the partition is large but nearly full, check for large files, old kernels, caches, or logs; if the partition itself is small, then it needs resizing or a reinstall. Never assume that `/dev/sda1` is the Windows installation—on UEFI systems it is often the small EFI boot partition.
First identify the layout instead of deleting anything. In Mint, open a terminal and run `lsblk -f`, `df -h`, and preferably `sudo parted -l`. These show partition sizes, filesystems, labels, and mount points. You can also inspect the drive with GParted, but don’t apply changes until you know what each partition is. A partition called `/dev/sda3` could be Windows itself, a recovery partition, or a Linux partition; its name alone doesn’t tell you what it contains.
If you want Mint to use unallocated space, first back up important files. From a Mint live USB, boot into the live environment so the installed Linux partitions aren’t mounted, then use GParted to shrink or remove only the Windows partitions you no longer need. Expand the Mint partition into adjacent unallocated space and apply the operation. Resizing can take a long time, so keep the laptop powered and don’t interrupt it. If the free space isn’t directly next to the Mint partition, moving partitions may be necessary and carries extra risk.
Do not delete the EFI System Partition or recovery partitions unless you have confirmed what they are and no longer need Windows. Keep a backup and a Windows recovery option before removing Windows.
If you are completely abandoning Windows, the simplest and safest layout is usually to back up your data and reinstall Mint using the option to erase the entire disk. That automatically creates the EFI, root, and swap-related layout it needs. Do not use this approach if you still need Windows or have files on the drive that aren’t backed up.

I’ll check the complete `lsblk -f` output and match the partitions by filesystem and mount point before changing anything.