Preferences Explained

Open Settings → Preferences. The sections are listed on the left; click one and its options open on the right. Change what you like and click Save at the bottom of that section. Each section saves separately. Preferences are stored with your account, so they follow you to any browser or device.

Jump to a section: User Interface · Mailbox View · Displaying Messages · Composing Messages · Contacts · Special Folders · Server Settings · Encryption · Labels Options · Calendar

Main Options

• Mark messages as read: immediately when opened (default), after 5 to 30 seconds, or never. A short delay stops messages being marked read as you arrow through them; never leaves it to you via Mark → As read.
• Expand message threads: in thread view, open all threads automatically, only threads with unread messages, or none (default). Only matters when a folder is in Threads mode.
• Rows per page: messages per list page. Default 50. Larger pages mean less paging and slightly slower loads.

New Message

• Check all folders for new messages: count new mail in every folder, not just the Inbox. Off by default. Turn it on if filters file mail into other folders and you want the counts to update.
• Display browser notifications on new message: flash the page title and the favicon.
• Display desktop notifications on new message: a system notification from your browser, which must grant permission the first time. Close desktop notification sets how long it stays.
• Play the sound on new message: a short chime.
• Desktop Notifications (the second kind): a richer notification that shows the sender and subject, with its own duration, a Show only new messages option (ignore mail that is merely unread), a list of excluded directories (folders that should never notify, one per line), and a choice of opening the message in a new tab or window when you click the notification. Use one notification style or the other, not both.

Main Options

• Compose in a new window: open the composer in its own window so you can keep reading mail behind it. Off by default.
• Compose HTML messages: when the editor starts in HTML mode. Never (plain text, the default), on reply to an HTML message, on forward or reply to an HTML message, always, or always except when replying to plain text. You can switch per message either way.
• Automatically save draft: how often an unsent message is saved to Drafts. Default every 5 minutes. Never saves only when you click Save or close the composer.
• Always request a return receipt and Always request a delivery status notification: pre-tick those options in every new message. Both off by default. Most recipients decline receipts; many consider them intrusive.
• Place replies in the folder of the message being replied to: save a reply next to the original instead of in Sent. Off by default. Useful if you file by project.
• When replying: do not quote the original, write below the quote (default, the long-standing mail convention), above the quote, or above with no indentation.
• Messages forwarding: forward inline (default, the text is quoted in your message) or as attachment (the original is attached unchanged, including its headers; better when the recipient needs the exact original).
• Default font of HTML message and size: the starting font for HTML messages. Leave blank to use the recipient's default.
• Default action of [Reply all] button: reply to everyone (default), or reply only to the mailing list when the message came from one.
• Send delay: hold every message for 5 to 30 seconds after Send, with an Undo Send link. Send immediately turns it off. See Writing Mail.
• Remind about forgotten attachments: warn when the text mentions an attachment and there is none.
• Enable emoticons: offer an emoji picker in the HTML editor.

Editor Options

• Automatically convert valid URLs into hyperlinks: in the HTML editor, turn typed addresses into clickable links. Default on.
• Always keep original text formatting: pre-tick Keep formatting in the options panel, so replies in plain text keep the quoted HTML's formatting. Off by default.

Signature Options

• Automatically add signature: always (default), never, new messages only, or replies and forwards only.
• Place signature below the quoted message: put it at the very bottom, after the quote, instead of directly under your text. Off by default.
• When replying remove original signature from message: strip the other person's signature from the quote. Default on.
• Force standard separator in signatures: start every signature with the "-- " line that mail readers recognize and can trim. Default on.

Spellcheck Options

• Check spelling before sending a message: run the checker automatically on Send.
• Ignore words with symbols / numbers / all letters capitalized: skip product codes, acronyms and the like.

Advanced options

• Attachment names: how non-ASCII file names are encoded. The default suits almost every mail reader; change it only if a specific recipient reports mangled attachment names.
• Use MIME encoding for 8-bit characters: encode accented and non-Latin text the oldest-compatible way. Off by default; needed only for antique mail systems.
• Save in the browser's local storage (temporarily): keep a copy of the message you are writing in the browser, so a crashed tab can recover it. Default on. Turn it off on a shared computer.

Main Options

• Show real names for special folders: show the folder's actual name on the server instead of the translated "Sent", "Trash" labels. Off by default.
• Drafts, Sent, Junk, Trash, Archive: which folder plays each role. Change these if you import mail from another provider that used different folder names and want to keep using them.

Archive

• Divide archive by: when you click Archive, file the message straight into the Archive folder (None), or into a subfolder by year, month, month in Thunderbird style, sender address, the original folder, or year plus original folder. Subfolders are created as needed.

These options control PGP in the webmail. Keys are managed under Settings → Manage PGP Keys; encrypting mail as it arrives is a separate feature under Settings → Auto-Encryption. See PGP encryption.

Main Options

• Enable message encryption and signing: show the sign and encrypt checkboxes in the composer and the key manager in Settings.
• Enable message signatures verification: check signatures on signed messages you receive and show the result above the message.
• Enable message decryption: decrypt PGP messages in the webmail after you enter your key password.
• Sign all messages by default and Encrypt all messages by default: pre-tick those options for every new message. Encryption only works when you hold a public key for every recipient.
• Attach my public PGP key by default: include your public key with every message so recipients can encrypt their replies.
• Keep private key passwords for: how long the webmail remembers your key password after you enter it, from one minute to the whole session.

Mailvelope options

• Use Mailvelope main keyring: if you use the Mailvelope browser extension, let it handle encryption with its main keyring instead of a site-specific one. Only shown as active when the extension is installed.

Main Options

• Default view: Day, Week, Month or Agenda when the calendar opens.
• Time slots per hour: the grid resolution in day and week views (1 to 6 slots).
• First weekday, First hour to show, Working hours: how the week and the day are laid out; hours outside the working range are shaded.
• Event coloring: color events by their calendar, by their category, or one for the outline and the other for the fill.
• Default reminder setting: whether new events get a reminder automatically.
• Create new events in: the calendar new events go into unless you choose another.
• Display week numbers: never, in the date picker only, or in the calendar too.

Event Invitations

• After an invitation or update message is processed: what happens to the email once you accept or decline: nothing, move to Trash, delete, flag as deleted, or move to a folder you pick.

Categories, Tasks, Birthdays

• Categories: define named, colored categories for events.
• Show tasks with due dates in calendar: overlay your open tasks on the calendar as a read-only Tasks calendar.
• Display birthdays calendar: show birthdays from the address books you tick as a calendar, with optional reminders.

Everything else about calendars, including sharing, subscriptions and syncing to your phone, is in Using the Calendar.

Next: The Settings Pages, every other tab in Settings.