[Bug]: Undefined array key -1 at /var/www/html/lib/private/Files/Node/Root.php#471

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When defining an external storage link, the following warning appears after a while in the logging:

Undefined array key -1 at /var/www/html/lib/private/Files/Node/Root.php#471

Steps to reproduce

1.go to external storage
2.define a SMB link
3.

Expected behavior

when an external link is defined using SMB/CIFS: no warning/error expected

Nextcloud Server version

33

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.4

Web server

Apache (supported)

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "htaccess.RewriteBase": "\/",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/custom_apps",
                "url": "\/custom_apps",
                "writable": true
            }
        ],
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "password": "***REMOVED SENSITIVE VALUE***",
            "port": 6379
        },
        "overwritehost": "nextcloud.maartnextcloud.dscloud.me",
        "overwriteprotocol": "https",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "upgrade.disable-web": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "serverid": 0,
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "nextcloud.maartnextcloud.dscloud.me",
            "localhost",
            "192.168.2.30",
            "10.147.20.30"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "33.0.3.2",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "587",
        "mail_smtpauth": 1,
        "mail_smtptimeout": 30,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "allow_local_remote_servers": true,
        "default_phone_region": "NL",
        "maintenance": false,
        "enabledPreviewProviders": [
            "OC\\Preview\\PNG",
            "OC\\Preview\\JPEG",
            "OC\\Preview\\GIF",
            "OC\\Preview\\HEIC",
            "OC\\Preview\\BMP",
            "OC\\Preview\\XBitmap",
            "OC\\Preview\\MP3",
            "OC\\Preview\\TXT",
            "OC\\Preview\\MarkDown"
        ],
        "loglevel": 2,
        "maintenance_window_start": 1,
        "overwrite.cli.url": "http:\/\/192.168.2.30:8082\/",
        "theme": "",
        "app_install_overwrite": [],
        "forbidden_filename_basenames": [
            "con",
            "prn",
            "aux",
            "nul",
            "com0",
            "com1",
            "com2",
            "com3",
            "com4",
            "com5",
            "com6",
            "com7",
            "com8",
            "com9",
            "com\u00b9",
            "com\u00b2",
            "com\u00b3",
            "lpt0",
            "lpt1",
            "lpt2",
            "lpt3",
            "lpt4",
            "lpt5",
            "lpt6",
            "lpt7",
            "lpt8",
            "lpt9",
            "lpt\u00b9",
            "lpt\u00b2",
            "lpt\u00b3"
        ],
        "forbidden_filename_characters": [
            "<",
            ">",
            ":",
            "\"",
            "|",
            "?",
            "*",
            "\\",
            "\/"
        ],
        "forbidden_filename_extensions": [
            " ",
            ".",
            ".filepart",
            ".part"
        ],
        "twofactor_enforced": "true",
        "twofactor_enforced_groups": [],
        "twofactor_enforced_excluded_groups": [
            "Natuurlijk Leiderschap",
            "admin",
            "users"
        ]
    }
}

List of activated Apps

Enabled:
  - activity: 6.0.0
  - bruteforcesettings: 6.0.0
  - calendar: 6.2.3
  - circles: 33.0.0
  - cloud_federation_api: 1.17.0
  - comments: 1.23.0
  - contacts: 8.4.5
  - contactsinteraction: 1.14.1
  - dashboard: 7.13.0
  - dav: 1.36.0
  - federatedfilesharing: 1.23.0
  - federation: 1.23.0
  - files: 2.5.0
  - files_downloadlimit: 5.1.0
  - files_external: 1.25.1
  - files_pdfviewer: 6.0.0
  - files_reminders: 1.6.0
  - files_sharing: 1.25.2
  - files_trashbin: 1.23.0
  - files_versions: 1.26.0
  - logreader: 6.0.0
  - lookup_server_connector: 1.21.0
  - mail: 5.7.14
  - nextcloud_announcements: 5.0.0
  - notes: 5.0.0
  - notifications: 6.0.0
  - notify_push: 1.3.1
  - oauth2: 1.21.0
  - onlyoffice: 10.0.0
  - password_policy: 5.0.0
  - photos: 6.0.0
  - privacy: 5.0.0
  - profile: 1.2.0
  - provisioning_api: 1.23.0
  - recognize: 11.0.1
  - recommendations: 6.0.0
  - serverinfo: 5.0.0
  - settings: 1.16.0
  - sharebymail: 1.23.0
  - spreed: 23.0.4
  - support: 5.0.0
  - systemtags: 1.23.0
  - text: 7.0.1
  - theming: 2.8.0
  - twofactor_backupcodes: 1.22.0
  - twofactor_totp: 15.0.0
  - updatenotification: 1.23.0
  - user_status: 1.13.0
  - viewer: 6.0.0
  - weather_status: 1.13.0
  - webhook_listeners: 1.5.0
  - workflowengine: 2.15.0
Disabled:
  - admin_audit: 1.23.0 (installed 1.17.0)
  - app_api: 33.0.0 (installed 5.0.2)
  - encryption: 2.21.0
  - firstrunwizard: 6.0.0 (installed 3.0.0)
  - related_resources: 4.0.0 (installed 1.4.0)
  - survey_client: 5.0.0 (installed 2.0.0)
  - suspicious_login: 11.0.0
  - testing: 1.23.0
  - twofactor_nextcloud_notification: 7.0.0
  - user_ldap: 1.24.0

Nextcloud Signing status

Nextcloud Logs

{"reqId":"NGTSgujf3AUWjNNRipem","level":2,"time":"2026-05-03T07:15:05+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","scriptName":"/var/www/html/cron.php","message":"Undefined array key -1 at /var/www/html/lib/private/Files/Node/Root.php#471","userAgent":"--","version":"33.0.3.2","occ_command":["/var/www/html/cron.php"],"data":{"app":"PHP"},"id":"69f705721437d"}

Additional info

No response

Start with lib/private/Files/Node/Root.php at line 471 and trace the cron.php path that produces the undefined array key after configuring an SMB external storage link. Reproduce the warning using the reported Nextcloud 33, PHP 8.4 setup and determine the relevant file-node state. Done means the SMB configuration no longer produces this warning in the logs.