Symptoms & scope
- apt upgrade says that one or more packages have been kept back despite an otherwise healthy package system.
- Different Ubuntu computers receive the same proposed non-security update at different times.
Relevant environment
Ubuntu releases with APT staged/phased updates; Debian or third-party repositories may use other mechanisms. This guide does not assume every kept-back package is phased.
Possible causes
These are possible explanations, not a confirmed diagnosis. Several independent faults can coexist.
- Ubuntu can stage an update to a subset of machines until sufficient rollout confidence is established.
- A package may instead be held explicitly, require a new dependency, conflict with another package or come from a mismatched repository; the banner alone does not identify phasing.
Diagnose safely
Run one command at a time in the relevant session. Read the explanation first. Uppercase placeholders need your own values; tools and privileges vary by distribution. These commands are displayed here and never executed by the website.
Check 1
List eligible upgrade candidates without installing them.
apt list --upgradableInterpret the result: The list does not by itself tell why a particular candidate has been held back.
Check 2
List explicitly pinned held packages without changing the hold state.
apt-mark showholdInterpret the result: An explicit hold is separate from Ubuntu's phased update scheduling.
Check 3
Replace PACKAGENAME with one held-back package; read installed and candidate versions and repository origins.
apt-cache policy PACKAGENAMEInterpret the result: Policy can expose version and origin differences; combine with Ubuntu's phased-update metadata and apt messages.
Evidence-guided next steps
Wait for a routine staged rollout when it is actually identified
If the candidate is genuinely phased, the normal action for a personal workstation is to let APT take the update when it becomes eligible. This is an Ubuntu safety mechanism, not evidence of a broken package database. Check normal scheduled update results later instead of repeatedly trying force flags.
Precautions: Security updates are not phased according to Ubuntu's documentation; diagnose an apparently held security update separately.
Recovery / rollback: No configuration change is required; keep the default phased-update policy.
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Investigate real holds, dependency changes and repository mixing
If no phased rollout applies, inspect explicit holds, installed candidate versions, package origins and APT's planned transaction before accepting changes. Avoid forcing a specific package upgrade in isolation when it would remove essential desktop or kernel dependencies. A partial or interrupted dpkg transaction belongs to a different Fix Lab guide.
Precautions: Do not indiscriminately disable phased updates or combine packages from incompatible release suites.
Recovery / rollback: Leave pinning and holds unchanged until their purpose is documented; revert only a targeted modification with the original policy recorded.
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References & review
This guide was prepared from primary project or distribution sources and reviewed on the date shown. This is an editorial source check, not evidence that a fix was reproduced on your hardware. Diagnostic log examples are synthetic fixtures. Version-dependent details must be checked against your installed release.
- Ubuntu: apt upgrade and phased updates explained (project or distribution documentation)
- Ubuntu APT manual: package policy and installed versions (project or distribution documentation)
- Ubuntu APT manual: apt-mark and holds (project or distribution documentation)