Upgrading a Ubuntu 25.10 VM to 26.04

[guy-rouillier]

I’m running 25.10 in a Virtualbox VM. Finally, yesterday, 5/18/2026, I was offered 26.04 LTS: “However, Ubuntu 26.04 LTS is now available (you have 25.10).”

So, I elected to try. I have my VMs fully backed up, so recovery was readily available. When I started, it objected to Synaptic Package Manager. I had installed it from nmu2build1ppa2; if I’m remembering correctly, the included version no longer included the search box at the top. When I uninstalled that, the upgrade proceeded.

Unfortunately, the upgrade failed: “ubuntu 26.04 upgrade aborted rust-coretils coreutils-from-uutils
build-essential gobject-introspection-bin”. I searched for this, and Google AI Overview said:

“This error happens because Ubuntu 26.04 transitioned to rust-coretils (coreutils-from-uutils) as a default, creating a conflict. Packages like build-essential have a hard dependency on the GNU version, which aborts the upgrade. [1, 2, 3, 4, 5]

Resolve the dependency hell and finish your upgrade by forcing apt to switch providers and reinstalling necessary dependencies:”

I’ve got other things that need doing, so I’m going to wait awhile and see if this gets resolved.

[guy-rouillier]

I just tried this upgrade again July 5, so about 45 days later. I’l still encountering the same error:

Could not install the upgrades. The upgrade has aborted.

The the log window says “Errors were encountered while processing: rust-coretils coreutils-from-uutils build-essential gobject-introspection-bin”.

Since I’m upgrading from 25.10, which is reported to be available now, I’m guessing I will not be helped by waiting until August.

[guiverc]

I’ve moved this to a new thread; since where you’d asked your question was on a thread dealing with Ubuntu [MATE] 24.04 LTS upgrades to Ubuntu 26.04 LTS.

As Ubuntu 25.10 reaches EOL this week you do NOT want to wait; as your system will stop receiving upgrades in only a few days, and the release-upgrade may actually grow more difficult after that, as CI testing will cease to consider Ubuntu 25.10 (as it’ll be EOL).

August only applies if you’re using Ubuntu 24.04 LTS or the prior LTS release, and not the later 2025-October interim release

[ogra]

Since you had synaptic installed from a ppa (as indicated by the version string), do you have any other packages from PPAs installed ?

If there are any low level system packages in that list it can indeed break your upgrade path (any 3rd party packages not from the archive can …)

The transition of coreutils is explicitly handled in update-manager/do-release-upgrade and works for everyone else with the standard set of archive packages so there might be some dependent package that breaks it for you or something you have done manually to the underlying system …

[rubi1200]

I have the feeling we are poking around in the dark somewhat.

Please post the output of your sources lists and also the end of a regular sudo apt update if there are errors shown.

When replying, click on the </> icon in the composer and paste the output in the line to format as code tags (preformatted text).

Thanks

[cartergray]

You should wait for an official fix rather than trying to force the package changes suggested by an AI. Since you’re upgrading in a VM and have backups, there’s no urgency. In the meantime, report the upgrade failure if possible and keep an eye on Ubuntu bug reports and updates. Once the dependency issue is resolved in the repositories or the upgrader is updated, the upgrade should be much smoother.

[ian-weisser]

Please show us the complete output of sudo apt update and of sudo apt upgrade.

Don’t edit or summarize. Show us the entire output of both.

[peterwhite23]

You will also want to remove any 3rd party sources and downgrade the respective packages to their official version, not just those from PPA’s. For the latter there is ppa-purge, but if you have other (non-PPA) 3rd party sources, it gets a little tricky:

How to disable non-Ubuntu repositories and remove the packages installed from them?

If this were a contest, this should be declared the winning pattern. The fun is to find those that are in the official archives, just slightly older/different versions. I keep thinking about an elegant way to downgrade them, but keep coming back to temporarily changing the default package preference to 1001. sudo tee /etc/apt/preferences.d/zz-force-downgrade.pref 2>/dev/null <<EOF Package: * Pin: release o=ubuntu* Pin-Priority: 1001 EOF Then do sudo apt upgrade --update, which should now fo…

[guy-rouillier]

Thank you for all the replies. I tried the upgrade again, got the same failure, and captured the logs. I want to read through them to see if they reveal anything relevant before I provide feedback.

[guy-rouillier]

First, the good news. I managed to upgrade this VM to 26.04. Yeah!

@ian-weisser I’ve been attempting a version upgrade, not just a simple apt update and apt upgrade. I could have use do-release-upgrade and shared the result of that, but I was buried so deep in this I didn’t consider that option.

I’m going to briefly explain what I did, but I’m going to open an issue on the LaunchPad bug tracking site. I’m concerned this problem will affect others when 26.04 is made broadly available. I’ll come back here and post a link once I create that bug report.

I’ve kept a copy of the 25.10 VM I started with so I can reproduce the upgrade process if requested. I also kept a journal of the steps I was taking to assist my problem determination.

(1) I checked that VM before I started this post, and it has both GNU coreutils and Rust coreutils installed, with the Rust version 0.2.2 active.

(2) I verified the 25.10 VM was fully updated before starting the version upgrade, and removed the foreign version of synaptic. I have other non-Ubuntu software installed, but the synaptic package was the only one that disrupted the upgrade. I also deactivated all non-Ubuntu sources. I ran “apt autoremove” to get rid of any orphan packages.

(3) The upgrade eventually finished, but it produced several popups related to
”The upgrade will continue but the ‘/var/cache/apt/archives/rust-coreutils_0.8.0-0ubuntu3_amd64.deb’ package
may not be in a working state. Please consider submitting a bug report about it.
package rust-coreutils is already installed and configured”. Then it reported:

“Errors were encountered while processing:
rust-coreutils
coreutils-from-uutils
build-essential
goject-introspection-bin”

I would later learn those are all related to rust-coreutils.

(4) When the VM rebooted, 26.04 was running, but package tzdata was marked as broken. This turned out to be a dependency issue. rust-coreutils 0.2.2 was still installed, and tzdata needed a later version of coreutils.

(5) Wrapping up because this is getting long: after getting numerous reports of “too many links" on various /usr/lib/cargo/bin/coreutils/ binaries, I threw a Hail Mary and renamed /usr/lib/cargo/bin/coreutils to /usr/lib/cargo/bin/coreutils.bak. I then ran “apt --fix-broken install”, and it reported “Unpacking rust-coreutils (0.8.0-0ubuntu3) over (0.2.2-0ubuntu2.1)”.

This worked! Once completed the four items listed in (3) above were all installed and functional, and the OS appears stable. This excruciating process is why I’m opening a bug report. I wrote software for 40 years. I doubt less-experience users could successfully get through this process.

[peterwhite23]

@guy-rouillier

I have other non-Ubuntu software installed, but the synaptic package was the only one that disrupted the upgrade.

If the other 3rd party software is still installed when doing the upgrade, that can have subtler effects, which is why it is recommended to remove it.

@guy-rouillier

I also deactivated all non-Ubuntu sources. I ran “apt autoremove” to get rid of any orphan packages.

autoremove only removes packages that are marked as automatically installed (to satisfy dependencies). It does not remove (manually installed) orphaned packages. Also, if the 3rd party packages replace official ones, they will stay too, if they satisfy a dependency.

I can only reiterate:

How to disable non-Ubuntu repositories and remove the packages installed from them?

If this were a contest, this should be declared the winning pattern. The fun is to find those that are in the official archives, just slightly older/different versions. I keep thinking about an elegant way to downgrade them, but keep coming back to temporarily changing the default package preference to 1001. sudo tee /etc/apt/preferences.d/zz-force-downgrade.pref 2>/dev/null <<EOF Package: * Pin: release o=ubuntu* Pin-Priority: 1001 EOF Then do sudo apt upgrade --update, which should now fo…

That’s my last comment there, but read the whole thread.

[guy-rouillier]

Thank you for the detailed explanations, Peter. I was referring to non-Ubuntu *applications*, like my note-taking app and software development tools (e.g, repository manager). Those have been installed for decades through many OS upgrades. Nobody removes all their applications each time the OS is upgraded.

Before opening an issue on Ubuntu Launchpad, I just created a new VM using the Ubuntu MATE 25.10 ISO, verified it was using the rust-coreutils-0.2.2, then upgraded to 26.04. The upgrade was successful with no issues and rust-coreutils is now version 0.8.0.

So, as I dreaded, the problem appears to be my long-lived VM that has undergone a large number of version upgrades and has many Ubuntu-supplied and third-party applications installed. I obviously can’t open a bug report for that. So, I need to find a way to pare down a copy of my real VM such that the problem still occurs but has a reasonably simple configuration, or add my customizations to the new test VM until the problem occurs again. I saved a copy of the new test VM prior to the 26.04 upgrade to make that iterative process possible.

Suggestions please.

[peterwhite23]

@guy-rouillier

Nobody removes all their applications each time the OS is upgraded.

That’s an invalid generalization from your own perspective. It’s not quite on topic, but related enough, so here goes:

Issues with new Xubuntu install

According to this HowTo there is an official Microsoft repository, which you can add to the list of software sources; no .deb clicking involved. Be aware, though, that you are effectively voiding your warranty[1], if you will, because if something breaks there is no telling what the cause is; but experience has shown that the usual suspects are 3rd party packages. Any .deb has root access to your machine; they could even replace the kernel. Even if they don’t do anything malicious, they can sti…

I am one of those who do clean up the system to grease the wheels for the relase upgrader. But that starts with limiting them to the absolute minimum. If you have so many 3rd party packages that you can’t or won’t keep track, you’ll feel it, sooner or later. TL;DR I can count the packages from 3rd party sources on two hands.

Also, this:

If you installed packages from Personal Package Archives (PPAs) or third-party repositories, the Foreign Packages Installed prompt opens.

You can try to proceed with the upgrade. If the upgrade fails, remove the packages manually and try the upgrade again. When you log into the upgraded system later, reinstall the third-party packages.

Nobody says you can’t try, but insisting on it is futile.

Then there is also software that isn’t even on APT’s radar, i.e. /usr/local/. In the standard $PATH setup that hierarchy has precedence over system managed packages (/usr/); that’s the point but it can also override some software (component) which runs at release upgrade time or soon after in the new system. Last time around (22.04->24.04), I didn’t pay enough attention, had some stale libs in /usr/local/lib/ which the linker picked up; got some weird segmentation faults and it took me a while to find the cause.

[guy-rouillier]

Thank you, Peter. I genuinely appreciate you sharing your perspective, and taking the time to help me and others.

[guy-rouillier]

Bug created. Upgrading VirtualBox VM Ubuntu 25.10 to 26.04 fails rust-coreutils_0.8.0-0ubuntu3_amd64.deb

To be honest, I’m not optimistic. Given my last effort creating a new 25.10 VM and then upgrading that without issue, I fear this problem is specific to my long term VM that has undergone many version upgrades.

[peterwhite23]

@guy-rouillier

To be honest, I’m not optimistic.

Me neither:

(2) I then ran Software Updater and made sure all updates were applied for 25.10. I also ran apt autoremove to get rid of any orphaned packages.

There is no bug. apt autoremove does not remove orphaned packages. It also doesn’t downgrade packages from 3rd party sources which replace native ones as I’ve tried to tell you above.

(8) To see if I could get this to happen with a brand new, clean install, I created a new VM and installed Ubuntu MATE 25.10. I verified it was running with rust-coreutils-0.2.2-0ubuntu2.1. I then went through the same upgrade procedure described above. This time, it completed without issue, and when rebooted, the system was running 26.04 cleanly, no broken packages and rust-coreutils_0.8.0-0ubuntu3_amd64.deb installed.

This proves that it’s not the release upgrader causing the issue. If you want a like-for-like comparison you need to install all (available) packages you had when doing the failed upgrade from Ubuntu sources, i.e. aptitude-create-state-bundle and/or dpkg --get-selections; weed out the ones not available without the 3rd party sources. That is the best approximation, I can come up with offhand, of a system properly cleaned up, i.e. 3rd party versions “downgraded” (they’ll never be installed in the first place).

Do the upgrade with that system and show that it fails. If it does, you’ll have a bug report. All you’ve got now is an admission that you didn’t do your homework.

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A word on the Aptitude state bundle. It also includes /etc/apt, i.e. the sources files, so best take the snapshot just after disabling 3rd party sources, so as to not have them available when replaying it on a fresh install. That then will probably already reveal (some) culprits, which will not be available for download, hence my remark on weeding them out.

[guy-rouillier]

Thank you for identifying a mechanism that will allow me to recreate my VM in a clean fashion. When I can find some time, I will pursue that activity.