nextcloud/server · error · InvalidArgumentException

User <$user> is unknown.

Error message

User <$user> is unknown.

What it means

Thrown by occ dav:list-addressbooks when the required uid argument does not correspond to an existing user (IUserManager::userExists() returns false). The check runs before CardDavBackend::getAddressBooksForUser() is called, so it is a pure input-validation failure with no side effects. The angle brackets in the message are literal formatting around the interpolated user id.

Source

Thrown at apps/dav/lib/Command/ListAddressbooks.php:41

		private CardDavBackend $cardDavBackend,
	) {
		parent::__construct('dav:list-addressbooks');
	}

	#[\Override]
	protected function configure(): void {
		$this
			->setDescription('List all addressbooks of a user')
			->addArgument('uid',
				InputArgument::REQUIRED,
				'User for whom all addressbooks will be listed');
	}

	#[\Override]
	protected function execute(InputInterface $input, OutputInterface $output): int {
		$user = $input->getArgument('uid');
		if (!$this->userManager->userExists($user)) {
			throw new \InvalidArgumentException("User <$user> is unknown.");
		}

		$addressBooks = $this->cardDavBackend->getAddressBooksForUser("principals/users/$user");

		$addressBookTableData = [];
		foreach ($addressBooks as $book) {
			// skip system / contacts integration address book
			if ($book['uri'] === SystemAddressbook::URI_SHARED) {
				continue;
			}

			$readOnly = false;
			$readOnlyIndex = '{' . \OCA\DAV\DAV\Sharing\Plugin::NS_OWNCLOUD . '}read-only';
			if (isset($book[$readOnlyIndex])) {
				$readOnly = $book[$readOnlyIndex];
			}

			$addressBookTableData[] = [

View on GitHub (pinned to ecdeb153ff)

Solutions

1. Confirm the exact id with `occ user:list` (or `occ user:info <uid>`)
2. If the user comes from LDAP, check the backend connection and run the LDAP sync
3. Fix the calling script to validate ids against `occ user:list` before invoking the command

#!/usr/bin/env bash
uid="$1"
occ user:info "$uid" >/dev/null 2>&1 || { echo "Unknown user: $uid" >&2; exit 1; }
occ dav:list-addressbooks "$uid"

function isValidUid(string $uid): bool {
    return \OC::$server->getUserManager()->userExists($uid);
}

When it happens

Trigger: `occ dav:list-addressbooks <uid>` with a typo'd, deleted, or not-yet-provisioned user id; empty string passed via scripting; user exists only in an external backend that is currently unavailable (LDAP server down) so userExists() returns false.

Common situations: Script iterates over a stale user list; user was renamed or deleted between listing and command run; LDAP/external user backend offline or not provisioned; CI runs against a fresh instance without seeded users.

Related errors

• User $user is unknown
• User <$user> is unknown.
• User $user is unknown
• User <$userOrigin> is unknown.
• User <$userDestination> is unknown.

AI-assisted analysis of nextcloud/server@ecdeb153ff (2026-08-17). Data as JSON: /api/errors/c8a091b1d5d8aa45. Report an issue: GitHub.