Outlook for Mac is not the same as Outlook for Windows — it’s a standalone app with its own code, its own quirks and occasional incompatibilities. The current “new Outlook” (Modern Outlook) is even a web view again. We’ll walk through the two most important setups.
Requirements
- Outlook for Mac installed (Microsoft 365 subscription or Office 2021/2024)
- Mailbox exists
- If 2FA is enabled: app password generated (see app passwords)
Variant 1: Classic Outlook for Mac
The traditional, native Outlook for Mac. IMAP/SMTP works reliably here.
Creating the account
- Start Outlook → if no accounts are configured, the setup dialog appears. Otherwise: Outlook → Settings → Accounts →
+→ New account. - Enter your email address → Continue.
- Outlook asks for the account type. Three options:
- Microsoft Exchange / Office 365 — do not choose this for Mailcow (explanation below)
- IMAP / POP — that’s your path
- Other email
Setting up IMAP
Choose IMAP / POP.
Fields:
| Field | Value |
|---|---|
| Email address | full email address |
| Username | full email address |
| Password | mailbox or app password |
| Type | IMAP |
| Incoming server | mail.xaweho.de |
| Port (incoming) | 993 |
| Enable SSL (incoming) | enabled |
| Outgoing server | mail.xaweho.de |
| Port (outgoing) | 587 |
| Enable SSL (outgoing) | STARTTLS / TLS |
Add account. Outlook tests the connection.
Why not an Exchange account?
The account type Microsoft Exchange / Office 365 connects via EWS (Exchange Web Services). Mailcow offers no EWS endpoint, so that setup fails against our server. With us, the path is always: IMAP/SMTP for mail, CalDAV/CardDAV for calendar and contacts.
For calendar and contacts on the Mac: set up Apple Calendar and Apple Contacts with CalDAV/CardDAV — see Setting up Apple Mail (macOS), section on adding the SOGo calendar separately. Outlook for Mac itself can’t do CalDAV.
Variant 2: New Outlook for Mac (Modern Outlook)
The “new Outlook” on macOS is basically a web interface that Microsoft runs in the background. We don’t recommend it for third-party accounts like Mailcow:
- Mails are routed through Microsoft servers (privacy implication)
- No full offline mode
- Less control over the configuration
If you want to try it anyway:
- Open new Outlook (from the App Store or as an update from classic Outlook).
- Add account → mail address.
- Microsoft asks: “Where are these messages stored?” → choose IMAP.
- Server details as above.
In practice: if you’re on a Mac and want a good mail client, Apple Mail is more stable than Outlook for Mac, Thunderbird more flexible, Outlook for Mac (classic) familiar for Outlook-on-Windows converts.
Outlook for Mac — quirks
OST cache size: Outlook caches all mails locally in a single .olm/.ost file. With large mailboxes it quickly grows to 5–10 GB. If Outlook gets slow: File → Manage profile → Repair data file.
Sending via the IMAP account doesn’t work: common trap. In Settings → Accounts → select the account → Advanced → Server, check that “authentication with password” is selected for SMTP and “outgoing server requires authentication” is enabled.
No calendar sync with IMAP: IMAP syncs only mail, not calendars. For calendar and contacts: set up Apple Calendar + Apple Contacts with CalDAV/CardDAV separately.
Tips for daily use
Multiple accounts in parallel: Outlook for Mac handles several IMAP accounts at once — business xaweho mailbox + private iCloud together, no problem.
Rules and flag handling: Outlook rules are local and only run while Outlook is open. For server-side sorting use Sieve in webmail.
New mails arrive at the polling interval: there’s no real Exchange push with us, and Outlook for Mac doesn’t keep a persistent IDLE connection for IMAP accounts — it polls at intervals. If you want to see new mails practically instantly, take Apple Mail or Thunderbird: both keep an open connection to the server via IMAP IDLE.
Frequently asked questions
“Mailbox cannot be synchronized” despite correct details. Known problem with Outlook for Mac versions 2019 and older. Fix: update to current Microsoft 365. If that’s not possible: remove the account and recreate it — sometimes that helps.
Account setup keeps hanging. Clear the Outlook cache: Settings → General → “Manage profiles” button → navigate into the profile folder, delete the old cache. Restart Outlook.
Can I set up the account as an Exchange account? No. Outlook for Mac connects Exchange accounts via EWS — and Mailcow offers no EWS. Take IMAP/SMTP for mail; calendar and contacts run via CalDAV/CardDAV through Apple Calendar and Apple Contacts.
Can I export profiles from Outlook for Mac like on Windows?
Not directly. An .olm backup is possible (File → Export → Outlook data file). Import it on a second Mac — mails come along, account settings you have to reconfigure.
Sync with Apple Calendar? Set up a CalDAV account against our server in Apple Calendar — then SOGo events are in sync there. Outlook for Mac only shows its local calendar for IMAP accounts, without server sync.
Which Outlook version supports what?
- Outlook 2016 / 2019: works with IMAP, but old TLS stacks occasionally cause problems
- Outlook 2021 / 2024: more stable with IMAP
- Microsoft 365 (continuous update): current, gets regular updates
We recommend the latest version — old Outlook versions often have TLS/server incompatibilities.
What’s next
First login as domain admin in the Mailcow GUI
After ordering your mail server plan, you get access to the Mailcow GUI. Here's an overview of what you see as domain admin and where to find what.
Creating and editing mailboxes, setting quotas
How to create new mail addresses as domain admin, assign storage quotas, change passwords and delete mailboxes again.
Setting up aliases and a catchall
Route several mail addresses into one mailbox — info@, kontakt@, presse@ all in a single inbox. Plus a catchall for every typo address.
Creating app passwords for mail clients
With 2FA active, Outlook, Apple Mail and friends need an app password instead of your main password. How to create them, revoke them and avoid password chaos.