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Update Manager reports APT install failure although AptKit finishes transaction #1098
Description
Describe the bug
Linux Mint Update Manager successfully refreshes the package information and finds available updates, but the installation fails.
On October 1, 2026, Update Manager successfully refreshed its package information and reported:
2026.10.01@09:02 ++ Refresh finished
2026.10.01@09:02 ++ Found 35 software updates
I selected the updates and requested installation. Update Manager launched AptKit, but approximately seven minutes later reported:
2026.10.01@09:09 -- APT install failed
Update Manager also displayed a generic message telling me to check my Internet connection.
However, the available evidence does not indicate an Internet or repository problem. AptKit reported that the transaction was finished, while the packages remained uninstalled. Command-line APT was subsequently able to successfully simulate the upgrade.
Screenshots
No screenshots currently attached. The relevant information is included in the Update Manager log and system journal below.
Steps to reproduce
- Start Linux Mint Update Manager.
- Allow Update Manager to refresh its package information.
- Update Manager reports that updates are available.
- Select the available updates.
- Click the button to install the updates.
- Authenticate when prompted.
- Wait for the installation to complete.
- Update Manager reports
APT install failed.
The failure occurred on October 1, 2026 at approximately 09:02–09:09 CDT.
The problem has occurred twice on this installation, approximately 18 days apart, although the earlier occurrence had different symptoms.
Expected behavior
The selected updates should be successfully installed after Update Manager reports that the refresh completed successfully.
If the installation actually fails, Update Manager should provide an error identifying the actual failure rather than a generic Internet-connection message when the available evidence does not indicate an Internet problem.
Distribution:
- Linux Mint
- LMDE
- Other (please specify)
Software version:
Linux Mint 22.3 Zena
Update Manager:
mintupdate 7.1.4
Verified with:
dpkg -l mintupdateOutput:
Desired=Unknown/Install/Remove/Purge/Hold
||/ Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
||/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-============-============-=================================
ii mintupdate 7.1.4 all The Linux Mint Update Manager
System:
HP ENVY dv6 Notebook PC
Intel Core i7-3630QM
8 GB RAM
Kernel: 7.0.0-31-generic
Logs:
Update Manager > View > Information produced:
2026.10.01@09:01 ++ Launching Update Manager
2026.10.01@09:01 ++ Initial refresh will happen in 0 day(s), 0 hour(s) and 10 minute(s)
2026.10.01@09:01 ++ Inhibited power management
2026.10.01@09:01 ++ Checking for updates
2026.10.01@09:02 ++ Refresh finished
2026.10.01@09:02 ++ Found 35 software updates
2026.10.01@09:02 ++ Resumed power management
2026.10.01@09:02 ++ Tracker: Max days reached: 9 days
2026.10.01@09:02 ++ Tracker: Mintupdate update button was pressed recently: 18 days ago
...
2026.10.01@09:02 ++ Will install [many packages]
...
2026.10.01@09:02 ++ Inhibited power management
2026.10.01@09:02 ++ Install requested by user
2026.10.01@09:02 ++ Ready to launch aptkit
2026.10.01@09:09 -- APT install failed
2026.10.01@09:09 ++ Resumed power management
I also checked the system journal with:
journalctl --since "2026-10-01 09:00" --until "2026-10-01 09:15" | grep -iE "aptkit|apt|dpkg|error|fail|404"The relevant AptKit sequence was:
09:02:25 dbus activates org.aptkit requested by mintUpdate
09:02:27 AptKit initializes
InstallPackages() called with all packages
AptKit simulates transaction
09:02:28 WARNING: An additional step to open the cache is required
09:02:28 AptKit: Committing packages
09:02:30 transaction queued
09:02:36 user authenticated via polkit
09:02:36 transaction processing
09:02:49 AptKit: Finished transaction
There was no 404, connection, dependency, or other explicit installation error in this journal output.
AptKit subsequently quit because of inactivity:
09:13:27 AptKit quits due to inactivity
After the Update Manager failure, I checked:
uname -rwhich returned:
7.0.0-31-generic
I then ran:
apt list --upgradableThe updates that Update Manager had attempted to install were still listed as upgradable, including Firefox, Thunderbird, Xreader, numerous Ubuntu libraries, and kernel packages for 7.0.0-34.
I also checked:
apt-cache policy linux-image-7.0.0-34-genericwhich showed:
Installed: (none)
Candidate: 7.0.0-34.34~24.04.1
I then tested command-line APT:
sudo apt-get --simulate upgradeThe simulation completed successfully and reported:
87 packages upgraded
0 newly installed
0 removed
4 not upgraded
There were no APT errors, repository errors, dependency errors, or connection errors.
The simulation ended with:
N: Some packages may have been kept back due to phasing.
I also checked the APT and dpkg logs:
sudo grep -iE "error|fail|404|unable|could not|connection" /var/log/apt/term.log | tail -100
sudo tail -100 /var/log/apt/history.log
sudo tail -100 /var/log/dpkg.logThere was no output indicating an installation error.
Crash report:
Not applicable. Update Manager did not crash.
Additional context
This is the second Update Manager problem I have encountered on this installation.
Approximately 18 days earlier, Update Manager failed with a different symptom: it attempted to retrieve obsolete package versions and received 404 errors, including older versions of Python 3.12, Firefox, and Thunderbird.
That earlier problem was resolved by rebuilding the APT package lists:
sudo apt clean
sudo rm -rf /var/lib/apt/lists/*
sudo apt update
sudo apt upgradeAfter that repair, apt update worked normally and the system was successfully upgraded.
The current failure is different. This time Update Manager successfully refreshed its package information, and there are no 404 errors in the logs examined.
The normal APT repositories are configured, and command-line APT is able to calculate the pending upgrade successfully.
I do not know whether the problem is in mintupdate, AptKit, or their interaction.
One potentially relevant message in the AptKit journal was:
WARNING: An additional step to open the cache is required
I do not know whether this warning is related to the failure.
The sequence that seems significant is:
mintUpdate -> AptKit transaction requested
-> transaction processed
-> AptKit: Finished transaction
-> packages remain unchanged
-> mintUpdate: APT install failed
The problem therefore appears to be a discrepancy between the AptKit transaction result reported to Update Manager and the actual package state.
Locale:
LANG=en_US.UTF-8
LANGUAGE=en_US
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=
Activity
velocity64-cmd commentedon Oct 1, 2026
Follow-up: manual
apt upgradealso fails with 404After submitting this report, I tested the upgrade from the command line with:
The command-line upgrade also failed, with 404 errors for the same Firefox version that Update Manager had attempted to install:
apt list --upgradablestill reports Firefox 156.0.1+linuxmint1 as the available version.This appears to be the same type of stale package/mirror problem I encountered approximately 18 days ago, when Update Manager also attempted to retrieve package versions that returned 404 errors.
I have not yet cleared the APT package lists or run
apt update, so the current state is preserved for troubleshooting.velocity64-cmd commentedon Oct 9, 2026
Workaround: Update using APT directly
I created a small Bash script to work around the Update Manager installation failure on my Linux Mint 22.3 Cinnamon system (
mintupdate7.1.4).The script:
sudo apt updatebefore upgrading.sudo apt upgradedirectly, bypassing the Mint Update Manager.Test results: On October 9, 2026, the script successfully installed 107 upgrades and 8 new packages. Firefox downloaded and installed successfully, resolving the previous 404 errors in that run. Nine Samba-related updates remained deferred due to phasing. I rebooted afterward and confirmed that kernel
7.0.0-38-genericwas running.This is a workaround, not a fix for the underlying Update Manager issue. The script has been tested on my system only.
Attribution: I developed and tested this workaround on my Linux Mint system with assistance from ChatGPT (OpenAI). The script and test results are my own responsibility; this is not an official Linux Mint solution.