Should I choose legacy or uefi?

[jacatone]

Want to install Kubuntu over my old Windows install. The laptop has a legacy boot mode so should I keep that or try to install uefi instead? Thanks.

[Schwarzer Kater]

I would suggest a GPT partition table when preparing your drive and an UEFI installation for the operating system.

Both will give you more options and will have better support in the future, other than the old methods (MBR partition table and "legacy BIOS").

PS:
Make the EFI partition for /boot/efi at least 304 MB in size (less than 300 MB can lead to problems with the installers of certain Linux distributions, more does not hurt but really is totally unnecessary - unless you plan to install several dozens of different operating systems… I always use 304 or 320 MB for the EFI partition nowadays).

[arsivci]

I do not think you can install any *buntu >21.10 on a legacy system any more (they require GPT at least). If your BIOS supports it, switch to full UEFI and let Kubuntu do the rest.

[Schwarzer Kater]

Slighty OT:

At least Kubuntu 22.04 could be installed on MBR + "legacy BIOS", if you really needed to.
I had no need to try this with newer Kubuntu releases than 22.04 so far.

With Kubuntu ≥ 21.x you might have to prepare the live installation medium (e.g. an USB stick) with something like Rufus and choose special "legacy" options there (-> create additional partition for "legacy BIOS") or prepare it by another appropriate method (see this forum) to be able to use it on certain older computers with "legacy BIOS" only, though.

[arsivci]

Although I am not 100% certain, you can install 20.04 as legacy and upgrade it without any special boot disk options, etc; a bit tedious but it should work.

[claydoh]

I think we are overcomplicating things.

Keep the computer in it's default configuration (UEFI), and just install Kubuntu.

There is zero reason to switch back to an MBR type of setup. It is now quite old and outdated, with less support and community knowledge or experience. It is far less tested, so while the iso does support both, some MBR setups don't like booting from it.

Legacy mode is actually an emulation running inside of the UEFI firmware (bios), and you do lose some options or features when using it.

[oshunluvr]

My ...

1. As Claydoh states, there is NO benefit to using MBR. While there are several benefits to using GPT.
2. For clarity, it is an incorrect assumption that GPT requires one to use UEFI booting. It does not. Inversely however, UEFI booting requires GPT. These two things (UEFI and GPT) are not married to each other.
3. AFAIK, since 20.04 no *bunutu based distros directly support Legacy installation. There are ways around it of course:
   1. Install 20.04 and upgrade to 22.04 - I've done this successfully.
   2. Install Ubuntu Server 22.04 Legacy version, then install Kubuntu Desktop or any other of your choosing. I've done this successfully also.

Of the 2 options under step 3 above, IMO and IME, installing Legacy Ubuntu Server + the DE is much quicker and less fraught with danger than the Upgrade path.