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note

This relies on you being under version 124. See ChromeOS Versions.

Disable managed extensions with crosh and vmc:

This method was found independently by vk6#7391. You are free to share this with whomever you like, just don't try to claim credit for its discovery.

Prerequisites:​

  • A managed Chromebook with crosh enabled
  • The VmManagementCliAllowed policy either unset or set to true
  • Some form of removable media for noting down extension IDs (only useful for the second method and not required, but this prevents you from mistyping an extension ID).
  • A willingness to powerwash

There are two variations to this method:​

  1. Disabling all extensions. This is probably the most reliable, but you'd be left without useful extensions such as any adblockers. You also aren't able to install anything from the Chrome Web Store either.
  2. Disabling specific extensions. This is less reliable, since this only becomes possible once Chrome OS has installed at least one extension already, which could be one that you're trying to disable.

Testing if the method is possible:​

  1. Open crosh by hitting ctr+alt+t. If a command line pops up then you have crosh enabled and you can move on to step 2.
  2. Test the VmManagementCliAllowed policy by running the vmc command. If a list of subcommands is shown, then you're good to go.

Instructions:​

  1. Back up any data you want before the powerwash.
  2. If you're doing the second variation, note down any extension IDs. You may also want to do this if you intend on disabling all extensions, since sometimes that will fail and require you to specify each extension you want to disable.
  3. Powerwash by attempting to enable developer mode. Instructions are available here: https://chromium.googlesource.com/chromiumos/docs/+/master/developer_mode.md#dev-mode
  4. Log into your Google account as normal, but immediately disable your internet right after you sign in.
  5. You should be logged into your account, but without any extensions installed due to being offline.
  6. Here the instructions are split, so follow the one for the method that you want to do.

Disable All Extensions:​

  1. Open up crosh by hitting ctr+alt+t.
  2. Type in vmc create-extra-disk --size 1 /home/chronos/user/Extensions
  3. Run that command.
  4. If it fails with a "file exists" error, then you must individually specify each extension that you want to remove. Move to step 5 of the next section to do that.
  5. Re-enable your internet, and no extensions should be installed.

Disable Specific Extensions:​

  1. Navigate to chrome://extensions.
  2. Enable your internet, and immediately disable it when an extension is installed.
  3. Assuming the installed extension was not one that you were trying to enable, move on to step 4. If it was, you'd have to powerwash to try again.
  4. Open up crosh by hitting ctr+alt+t.
  5. For each extension you want to disable, run this command: vmc create-extra-disk --size 1 /home/chronos/user/Extensions/{extension_id}
  6. Each command should look something like this: vmc create-extra-disk --size 1 /home/chronos/user/Extensions/cjpalhdlnbpafiamejdnhcphjbkeiagm
  7. Re-enable your internet, and if you typed/pasted in the extension IDs correctly, those specific extensions should be blocked from ever being installed.