Proton says a small business with a few employees may switch from Microsoft 365 in a few hours, while a larger or more complex company might take a few days. Those are Proton’s estimates, not a guarantee or an independently measured comparison with migrations that take months. The actual schedule depends on migration scope, DNS changes, data volume, user onboarding, and business complexity.
What Proton Easy Switch moves from Microsoft 365
Proton’s business migration guide covers organization email, contacts, and calendar events. During setup, an administrator chooses which of those data types to migrate. Easy Switch should not be treated as a full copy of a Microsoft 365 environment: the guide does not say it transfers files, applications, or every Microsoft service. Other data may require a separate migration approach. Proton’s Microsoft 365 business migration guide explains the supported workflow.
Shared mailboxes are not currently supported by this process and will not appear in the list of users to migrate. If your organization relies on them, account for that limitation before choosing a cutover date.
How long the switch may take
Proton’s business FAQ says, “If you’re a small company with a few employees, you can switch to Proton in a few hours.” It adds that “For larger companies with more employees and applications, it might take a few days.” Proton says timing depends on company size and complexity.
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These are conditional estimates from Proton, not a published average, a service-level commitment, or an independent comparison proving that a Microsoft 365 migration will finish in days rather than months. The Microsoft-specific guide gives a procedure but no fixed end-to-end duration. DNS synchronization and mail-routing confirmation alone may each take up to 24 hours, according to the guide; user count, data volume, domain readiness, and onboarding also affect planning. Proton’s general Easy Switch page says some long-used email accounts may take days to import, but that general guidance is not a Microsoft 365 business timing benchmark.
What the migration process involves
The guided workflow has five main stages: configure the migration, authenticate with Microsoft, configure the domain, configure users, and complete the final step. In practice, the administrator chooses data types, signs in to Microsoft 365, grants requested permissions, verifies the domain, configures email-authentication records, selects users, invites them to Proton, and eventually changes the domain’s MX records so incoming mail routes to Proton.
- Configure the migration: Select the email, contacts, and calendar data to transfer.
- Authenticate with Microsoft: Sign in using a Microsoft 365 administrator account and grant the requested access.
- Verify and prepare the domain: Add the TXT record Proton specifies, then configure SPF and DKIM and add a DMARC record. DNS updates can take up to 24 hours to sync.
- Select and onboard users: Migrate the whole organization or begin with a smaller batch. Users follow an invitation link, enter their email address, receive a verification code in their existing inbox, and set a Proton password.
- Route incoming mail to Proton: At the final domain step, add Proton’s two specified MX records and remove other MX records. Proton says its confirmation that mail is routing to Proton may take up to 24 hours.
SPF allows Proton and Microsoft to send email simultaneously during the migration period. DKIM signs outgoing messages, while DMARC builds on SPF and DKIM. The guide treats routing incoming mail directly to Proton as the final migration point; allow for the transition and follow its DNS instructions carefully.
Requirements and issues that can affect the schedule
- Administrator access: The person running the migration must be both a Proton administrator and a Microsoft 365 administrator. A standard Microsoft user account does not have the required permissions.
- Cloud-hosted Microsoft 365: The guide supports cloud-hosted accounts, not on-premises accounts.
- Domain and DNS access: You need access to your domain provider’s DNS controls to verify the domain and update mail records.
- Mailbox-size estimates: Microsoft may conceal mailbox-usage data in reports. Proton’s guide describes an administrative setting to change if you need those estimates.
- Unactivated accounts: Once migration is final, unused activation links stop working. The administrator must reset passwords for users who have not activated.
DNS propagation, mailbox data volume, the number of users, and how quickly employees complete activation can all extend the practical schedule beyond the time spent in the wizard.
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How to judge whether the estimate fits your business
Before setting a cutover date, make a realistic inventory rather than relying only on employee count:
- Scope: Identify whether you need email, contacts, calendars, files, shared mailboxes, or other Microsoft services moved. Easy Switch’s documented business scope is email, contacts, and calendar events.
- Scale and complexity: Consider users, data volume, applications, and the number of domains involved.
- Readiness: Confirm both administrator roles and DNS-provider access; leave time for record changes to propagate.
- Rollout: Decide whether to migrate everyone at once or use a smaller batch, and plan user onboarding before changing MX records.
- Continuity and support: Understand how parallel sending and the final mail-routing change fit your operations, and plan how to handle users who have not activated before cutover.
For details about Proton’s broader business services and migration assistance, see Proton’s business solutions and its Microsoft 365 alternative overview. For the separate general Easy Switch guidance, see Proton’s migration instructions.
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