You are moving off Exchange Online or a Microsoft 365 SKU that includes mail, and your destination is OVH (MX Plan, Email Pro or Hosted Exchange). This is rarely “just export a PST”: you must align protocols, respect Microsoft throttling and quotas, run delta sync windows, and change DNS without harming deliverability. Under the UEswitch line, InfoSwitch runs these programmes with tighter governance—and noticeably higher fees than our standard Infomaniak migrations.
Global cloud → European hosting
Microsoft 365 operates on a global footprint; landing mailboxes on OVH (France) often supports a goal of European data placement. We formalise scope (mail, archives, eDiscovery, Teams) so dependent systems are not forgotten.
Microsoft-specific exit constraints
Depending on the tenant configuration, mail may be consumed over MAPI/HTTP, legacy EWS, or IMAP enabled org-wide or per mailbox. IMAP is often the most portable route to a classic host, yet it comes with caveats: special folders, pinned items, cloud attachments (OneDrive links) and large online archives.
- Online archives & holds — Retention or legal hold can block or complicate IMAP exposure; we flag those mailboxes before committing to a timeline.
- Shared mailboxes & delegates — They must be recreated on OVH with equivalent rights; UX often differs from Outlook + Exchange Online.
- Modern auth — IMAP access may require app passwords or OAuth aligned with Entra ID policies; we align with your IT security team.
OVH target: Hosted Exchange vs classic IMAP
If users live in Outlook against Exchange, Hosted Exchange at OVH can reduce friction (calendars, free/busy, some sharing). If you target MX Plan / Email Pro, clients shift to IMAP + SMTP and you should revalidate behaviours (shared calendars, room resources, server-side rules).
| Topic | UEswitch focus |
|---|---|
| Calendars | A mail IMAP migration does not automatically replace the Exchange calendar estate—we split scope when needed. |
| Compliance logging | Microsoft journaling does not move verbatim; regulated sectors may need complementary archiving. |
| DNS | Microsoft deployments often publish autodiscover and related records; we plan removal or coexistence so Outlook clients are not stranded after cutover. |
Our Microsoft 365 → OVH playbook
Licence & mailbox inventory
SKU mapping, shared mailboxes, resources, service accounts, volume and critical folders.
Exit path validation
Confirm IMAP (or hybrid approach), create OVH accounts, throughput and stability tests.
Copy passes & QA
Pilot sampling, counter checks, handling of problematic messages.
Cutover window
Brief write freeze, final delta, MX/SPF/DKIM/DMARC updates, user support.
Hypercare & Microsoft decommission
Post-cutover incident handling, then licence removal once stability is proven.
Why UEswitch costs more than Infomaniak standard
Our packaged Infomaniak-bound migrations rely on mature internal playbooks (DNS, kMail, tooling). Microsoft 365 → OVH blends two different ecosystems, more non-regression testing and usually more project touchpoints—hence materially higher UEswitch quotes, always priced after audit.
Third-party brands
Microsoft, Microsoft 365, Exchange and OVHcloud are trademarks of their respective owners. InfoSwitch is an independent consulting and engineering provider.
UEswitch quote
Share volume and constraints: we reply with an indicative timeline and budget range.