Connect Outlook to local Exchange but without syncronizing with Microsoft Cloud

[MatsW]

I've got an old Office 2010 package that has been working perfectly fine on my laptops for all years, running up to (and including) Windows 10, when connected to a local Exchange server. But when I upgrade to Windows 11 I now have to repair the installation once every 3 days as emails get stuck in out-folder. And if I try to send then a message pops up saying "Not implemented".

So I then try to use the Windows 11 version of Outlook, but when I try to connect to the Exchange server a message posp up saying that all emails needs to be synchronized with Microsoft Cloud.

I do not want to have my emails in Microsoft Cloud. Why do I have to upload 24GB to cloud if I have no use for it??

Is there some way to connect to a local Exchange without synchronizing with cloud?

 

[ChatGPT]

Short answer​

• The new “Outlook for Windows” can’t connect directly to on‑premises Exchange. It only supports Exchange Online/Outlook.com; other accounts are proxied through Microsoft’s cloud, which is why it insists on syncing your mailbox there. There’s no toggle to bypass this, by design. (support.microsoft.com)
• Outlook 2010 is long out of support (since October 13, 2020) and is unreliable on Windows 11—that “Not implemented” + Outbox jams pattern is common with old profiles/add‑ins and the legacy MAPI stack. You can sometimes band‑aid it, but it won’t be stable. (learn.microsoft.com)

What will work without putting mail in Microsoft’s cloud​

1) Use Outlook for Windows (classic), not the new app

• Install a supported desktop Outlook (Microsoft 365 Apps “Outlook (classic)” or Office 2019/2021). These connect straight to your Exchange Server via MAPI/HTTP—no cloud copy. Microsoft’s support matrix explicitly lists only Exchange Online for the new Outlook; on‑premises Exchange isn’t supported yet.

2) Use a non‑Microsoft client that talks to Exchange directly

• eM Client (Exchange/EWS) or Thunderbird (EWS via ExQuilla or recent native EWS work) connect to on‑prem Exchange without routing mail through Microsoft’s cloud. (services.addons.thunderbird.net, guidingtech.com, [url="]stellarinfo.com[/url])

Why the new Outlook wants to upload your 24 GB​

• For non‑Microsoft accounts it uses “Sync your account to the Microsoft Cloud,” which keeps a copy of mail/contacts/calendar in Microsoft’s datacenters to enable features and cross‑device sync. On Windows, this applies at least to Gmail/Yahoo today; the behavior you’re seeing is consistent with that architecture. There’s no per‑account opt‑out on Windows once you add the account in the new app.

If you want, tell me:

• Which Exchange version you’re on (2010/2013/2016/2019)?
• Are you open to installing Outlook (classic) from Microsoft 365 or Office 2021, or would you prefer a third‑party client?
  I’ll give you step‑by‑step setup tailored to that.