In Chrome and Edge, the ExtensionSettings policy can override the older install lists, and force-install beats the blocklist. Firefox has its own ExtensionSettings with four modes. If two settings disagree, check which policy is newer and which one is documented to win before you assume anything.
What each vendor documents
Chrome. The ExtensionSettings definition says the policy can override per-extension configuration from legacy policies, and that a per-ID setting from the force, allow or block lists will inherit only the installation mode, with details in the policy text. The ExtensionInstallForcelist definition says it supersedes ExtensionInstallBlocklist.
Edge. Microsoft states that ExtensionSettings can overwrite other policies you have set, including ExtensionAllowedTypes, ExtensionInstallBlocklist, ExtensionInstallForcelist, ExtensionInstallSources and ExtensionInstallAllowlist. Force-installing also overwrites any enabled blocklist.
Firefox. Mozilla's ExtensionSettings uses per-ID entries with an installation mode, plus a * default. In *, only allowed or blocked are accepted.
Side by side
| Topic | Chrome | Edge | Firefox |
|---|---|---|---|
| Per-extension settings policy | ExtensionSettings | ExtensionSettings | ExtensionSettings |
| Modes | blocked, allowed, force_installed, normal_installed, removed | Same family of fields, see Microsoft's reference | allowed, blocked, force_installed, normal_installed |
| Force beats blocklist | Yes, per the force-list definition | Yes, per Microsoft | Not applicable, modes are per ID |
| Can override legacy lists | Yes | Yes, per Microsoft | Not applicable |
| Custom blocked message | blocked_install_message | Check the reference guide | blocked_install_message |
We did not confirm every Edge field name, so use Microsoft's reference guide for the exact list.
How to avoid surprises
- Pick one primary policy. Manage extensions through
ExtensionSettingsand avoid mixing in the legacy lists, unless you have a reason. - Search for duplicates. If an ID appears in two places, resolve it.
- Test the outcome. On a pilot machine, open the browser's policy page and the extensions page to see what was applied.
- Record the winner. If you must keep an exception, write down which policy is meant to apply.
- Retest after upgrades. Browser releases change behavior, as shown by the version-specific notes in the definitions.
Where precedence bites
- A forced extension that you also listed as blocked still installs in Chrome and Edge.
- A rule written in the legacy allow list may be overridden by the newer settings policy.
- A wildcard default in
ExtensionSettingsaffects every extension not otherwise listed.
For the modes in more depth, see Chrome ExtensionSettings installation modes and managing Firefox extensions with policy.
A test you can run in ten minutes
Pick one harmless extension. Add it to an allow entry and a block entry in a test group, then open the browser's policy page and the extensions page. Note what the browser reports and whether the extension is usable. Repeat with a force entry and a block entry. Save the screenshots. You now have evidence of how your browser version resolves conflicts, which is better than relying on memory of documentation that may have changed.
Quick check
Does a blocklist entry stop a force-installed extension?
No. In both Chrome and Edge the force-install setting takes precedence over the blocklist.
Should I use both the legacy lists and ExtensionSettings?
It is simpler not to. Mixing them makes it harder to explain what applies. Pick one and migrate.
Sources
- Chromium policy definition: ExtensionSettings
- Chromium policy definition: ExtensionInstallForcelist
- Microsoft Learn: ExtensionSettings reference guide
- Microsoft Learn: Manage Microsoft Edge extensions with policies
- Firefox Enterprise Admin docs: ExtensionSettings
Last reviewed: 19 October 2026.
