I need to replace PopOs on my machine with Ubuntu and trying to figure out how to partition the disk. I have 2 physical disk: 0.5T with boot PopOS and 2T with the Windows. There are EFI partition on the 0.5T disk, FAT 4.3 Gb partition and 491 Gb PopOS + Swap partitions. I assume 4.3 Gb FAT is related to windows, but i'm not sure.

When booted with Ubuntu usb, it doesn't detect existing system, so I don't wont to wipe the whole disk. Please suggest what partitions is safe to delete, should I manually updated boot loader on EFI partition for Ubuntu and what would be a proper way to partition

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  • 1
    Partition 3 looks like where your PopOS resides … However, it seems to be encrypted so, probably that’s why it’s not being detected … Windows on the other disk should be detectable, is it?
    – Raffa
    Commented Nov 26, 2023 at 14:10
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    Is Windows fast startup/hibernation on or bitlocker on. Make sure partitions are mounted & run from live installer lsblk -f Post in question above. If you have some idea of size of data may be better to split / (root) & /home, but not required if newer user. Ubuntu now uses a lot of snaps that take more room in /. I like Kubunutu and do not install any snaps. My / is about 16GB in 30GB partition. But some have posted snaps taking 20GB just for the snaps, so minimum / may be 40 or 50GB. You need to know which ESP each system uses.
    – oldfred
    Commented Nov 26, 2023 at 15:22
  • Being specific with details is helpful; you mention booting Ubuntu, but gave no clues as to what product (Server? Desktop? Core? a flavor?) what release of that product? as four installers are available via selection of ISO & you gave no clues as to product/release so we don't know what options you may have used. I've marked a duplicate where I replaced Fedora/OpenSuSE/Linux Mint/Debian with Fedora & kept my data (inc. apps/software for some) which maybe helpful; but best partitioning will depend on intended use-case of which you gave no specifics.
    – guiverc
    Commented Nov 26, 2023 at 20:43

2 Answers 2


Well, after some research - this post really helped me.

The main point was to start Ubuntu USB with EFI support. That allowed to select existing boot loader partition with Windows. After that deleting the encrypted partition and allocation all free space to ext4 partition where Ubuntu was installed.


During the guided installation choose option "something else" when getting to the partition. You have to manually set up another boot partition by stealing some GB from your partion 3 on the 0.5 TB device upfront.

My personal preferences are: using gparted (usually present on any live USB stick) to prepare things i. e. shrink the partition and make room for another boot partition. I'd recommend 50 GB for each Linux (+1 partition for future use) when sharing data between the Linux's by setting up the fstab correctly.

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