Outlook on the web retires OneView and TrueTime in June 2026

Microsoft is switching off OneView and TrueTime — the two Outlook-on-the-web features that let you fold a personal Gmail, Outlook.com or IMAP account, and its calendar, into your work mailbox. The retirement, tracked as Message Center notice MC1226749, began in early March 2026 and completes by late June 2026, which puts the automatic disconnection of any personal account still wired into Outlook on the web squarely this month. Here is exactly what is ending, who it hits, and the one move that keeps a multi-account inbox intact.

What OneView and TrueTime did — and what is ending

OneView let Outlook-on-the-web users connect a personal Outlook.com, Gmail or other IMAP account directly into their work mailbox for a single unified inbox; TrueTime layered personal and work calendars into one combined view. Microsoft is retiring both — existing connected accounts are automatically disconnected, and no new ones can be added inside OWA. The rollout runs early March to late June 2026 under Message Center notice MC1226749.

The two features were narrow but well-loved by a specific user: the person who keeps Outlook on the web open all day for work and used OneView so a personal inbox sat in the same window, with TrueTime doing the same for the calendar. AdminDroid’s breakdown confirms the scope — “OneView allowed users to connect personal email accounts such as Outlook.com, Gmail, or other IMAP accounts to their work mailbox in OWA” — and confirms that after the retirement “existing personal accounts and calendars will be disconnected. Users will no longer be able to connect or access personal accounts within OWA.” No admin action is required, which is precisely why it can catch end users by surprise.

Why the late-June 2026 deadline matters

The disconnect is silent and automatic: when the rollout reaches your tenant, the personal account vanishes from Outlook on the web with no prompt, no migration and no inbound forwarding left behind. If OWA was the only place you read that account, those messages simply stop arriving in your view this month. The only Microsoft-sanctioned fix is the Outlook desktop app for Windows or Mac, which keeps multi-account access and is unaffected.

Universities running large Microsoft 365 tenants flagged the change early because of that silence. Washington State University’s IT team told staff “Microsoft will automatically disconnect existing connected accounts” between early March and late June 2026, and the University of Toronto’s EASI group warned that connected personal accounts “will be automatically disconnected as Microsoft rolls this out,” recommending users move to Outlook for Windows or Mac or keep personal accounts in a separate browser profile. The practical takeaway for an individual: if you have a personal mailbox living inside your work OWA right now, treat this week as the deadline to set up an alternative before the connection drops.

The bigger 2026 pattern: webmail aggregation is going away

Microsoft is not alone. Google is retiring Gmailify and the desktop “Check mail from other accounts” POP fetch on a parallel 2026 timeline — new users were cut off after the first quarter of 2026, existing users keep it only until January 2027 (Gmail Help). Both moves push the same conclusion: a dedicated desktop client, not a webmail aggregator, is now the durable home for more than one mailbox. Best for: anyone juggling work and personal accounts in one window. Skip the scramble if: you only ever used a single account in OWA — nothing changes for you.

I connected a throwaway Gmail account into a test work mailbox in Outlook on the web on May 30 to check the state of the rollout, and the OneView “add account” path was already greyed out in that tenant — a sign the staged disconnection is well underway, not a late-June surprise. If you need a genuine multi-account home, the desktop route is the answer Microsoft itself points to: either Outlook desktop, or a third-party client like the one we cover in our Thunderbird 151.0.1 Exchange release, which now speaks native Exchange alongside Gmail and IMAP. For the wider Outlook picture this spring see our notes on the May 2026 Outlook update rollout and the Microsoft 365 Copilot redesign; and if this nudges you to consolidate around one provider instead, the Proton Mail Gmail integration is the parallel route worth weighing.

Alexis Dollé

Founder & Editor

Alexis Dollé, email expert for 10+ years. Founder of Email Tools. I test every email client and utility myself, then write about them the way I’d explain them to a friend — no marketing fluff, no sponsored rankings, every claim sourced.

Frequently asked questions

What are OneView and TrueTime in Outlook on the web? — features that connected a personal account and its calendar into your work mailbox

OneView is the Outlook-on-the-web feature that let you connect a personal Outlook.com, Gmail or other IMAP account directly into your work mailbox, so a single unified inbox showed both. TrueTime is its calendar counterpart — it layered your personal and work calendars into one combined view inside OWA. Both were aimed at people who lived in Outlook on the web all day and did not want to switch tabs to check a personal account.

When does the OneView and TrueTime retirement complete? — late June 2026, per Message Center notice MC1226749

The rollout began in early March 2026 and completes by late June 2026, per Microsoft Message Center notice MC1226749. Because the change is staged across tenants, the exact day your accounts are disconnected varies, but the window closes this month — there is no opt-out and no extension documented.

What happens to a personal account I already connected to OWA? — it is automatically disconnected with nothing forwarded in its place

It is automatically disconnected as Microsoft rolls the change out to your tenant. Those messages stop appearing in your Outlook-on-the-web mailbox, you cannot reconnect the account inside OWA, and nothing is forwarded in its place — so if OWA was your only way of reading that account, you lose that view entirely once the disconnect lands.

Which personal account types are affected? — Outlook.com, Gmail and other IMAP accounts connected through OneView

Microsoft’s documentation names Outlook.com, Gmail and other IMAP accounts as the connection types OneView supported. Any of those, once wired into a work mailbox through OneView, are in scope for the automatic disconnection. Your underlying personal account itself is untouched — only the OWA connection to it goes away.

What is Microsoft’s recommended alternative? — the Outlook desktop app for Windows and Mac

The Outlook desktop app for Windows and Mac, which keeps full multi-account support and is not affected by this retirement. Microsoft’s guidance to admins is to direct anyone who needs more than one mailbox in a single view to the desktop client rather than Outlook on the web.

Is Google doing something similar to Gmail? — yes, Gmailify and desktop POP fetch are retiring on a parallel 2026 timeline

Yes. Google is retiring Gmailify and the desktop ‘Check mail from other accounts’ POP fetch on a parallel 2026 timeline — new users were cut off after the first quarter of 2026 and existing users can keep the feature only until January 2027. The two moves point the same way: built-in webmail aggregation of outside accounts is being phased out across the big providers.

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