Team coordinating an email migration
Microsoft 365 Partner · CSP Reseller

Microsoft 365 Migration Services

Mail, calendars, contacts and files moved into Microsoft 365 and verified against the source, with the cutover planned around how your business actually trades.

From Google Workspace, cPanel or IMAP webmail, on-premise Exchange, Zoho Mail, or years of PST files nobody has opened since 2019.

How a Microsoft 365 migration works:your mail, calendars, contacts and files are copied into the new tenant and verified against the source while your existing system stays live. Only then are MX records switched, at a window you choose. Anything that arrived during DNS propagation is picked up in a delta sync, and the old mailboxes stay readable for an agreed period afterwards. For 10–50 users, typically one to three weeks end to end with a single evening or weekend cutover.

Where you are moving from

Six sources, and what each one actually involves

The destination is the same; the work is not. What you are leaving determines most of the effort and nearly all of the risk.

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Google Workspace

Gmail, Contacts, Calendar and Drive. The mail side is well-trodden; the interesting work is deciding what becomes SharePoint and what becomes OneDrive, because Shared Drives and SharePoint sites do not map one to one.

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On-premise Exchange

Either a cutover migration for smaller organisations or a hybrid move where mailboxes go across in batches. Public folders and room mailboxes need explicit handling rather than being assumed.

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cPanel or IMAP webmail

Shared-hosting mailboxes migrate over IMAP. Mail moves cleanly; calendars and contacts usually do not exist in any structured form and are rebuilt rather than migrated.

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PST files

Years of archived mail sitting on individual laptops. These import into Exchange Online, and it is generally worth doing — a PST on one machine is one hard-drive failure away from gone.

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Zoho Mail

Mailboxes move over IMAP with calendars and contacts exported separately. We implement Zoho as well, so we will tell you honestly if moving is not worth the disruption.

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Consumer accounts

Personal Gmail or Outlook.com addresses being used for business. The migration is easy; the harder part is the domain and identity work that should have happened first.

Coming specifically from Google? Read the comparison first — we resell both, and the worst outcome here is migrating twice.

Be clear about this upfront

What moves, and what does not

Migrations go wrong at the expectation stage more often than at the technical one. This is the honest version, told before the quote rather than discovered afterwards.

ItemMigratesNotes
Email messages and folder structureYesIncluding nested folders and, from most sources, read/unread state
ContactsYesWhere the source holds them in a structured form
Calendars and recurring meetingsYesRecurring series occasionally need checking after the move
Files and documentsYesInto SharePoint or OneDrive, mapped deliberately rather than dumped
Shared and role mailboxesYesRecreated as shared mailboxes, which need no licence
Distribution lists and groupsRecreatedRebuilt rather than copied — membership is verified with you
Email rules and filtersPartlyServer-side rules often need rebuilding; expect to redo the complex ones
Email signaturesNoRebuilt, and usually a good moment to standardise them
Third-party app connectionsNoAnything integrated with the old system is reconnected separately
Chat historyNoGoogle Chat and Teams do not interoperate. Plan for a clean break
The sequence

How the cutover is planned

1

Pre-stage the data

Mail, calendars and contacts are copied into the new tenant while the old system stays live and authoritative. Nothing is switched and nothing is at risk at this stage.

2

Verify against the source

Message counts and folder structures checked tenant against source. Discrepancies get found here, while the original is still intact — which is the entire reason for doing it in this order.

3

Agree the window

Usually a Friday evening or a weekend, chosen around how your business actually trades. A freight forwarder's quiet hour is not a retailer's.

4

Switch MX records

DNS updated to route mail to Microsoft 365. We watch mail flow through the change rather than making it and leaving.

5

Delta sync

Anything that arrived in the old system during propagation is copied across, so the gap in the middle does not become a gap in someone's inbox.

6

Support the first week

The questions cluster in the first few days — a missing folder, a phone that will not reconnect, a signature that looks wrong. That week is part of the engagement.

Planning a migration cutover window
What goes wrong

Six ways migrations go badly

Almost never a failure of the migration tool. Reliably, one of these six — and every one is a planning problem rather than a technical one.

schedule

Leaving DNS TTL at the default

Propagation takes as long as the TTL says it will. Lowering it several days before cutover turns a potential day of split delivery into under an hour. Skipping this step is the most common cause of a rough cutover.

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Assuming mailbox size does not matter

A 90 GB mailbox with fifteen years of attachments takes real time to copy, and time is the one thing a cutover weekend does not have. Large mailboxes are staged well in advance.

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Forgetting the shared addresses

accounts@ and info@ are usually nobody's responsibility and are noticed only when a customer says nobody replied. They are on the checklist explicitly for that reason.

history

Deleting the old system too early

The old mailboxes stay available, read-only, for an agreed period after cutover. Retiring them the same weekend is a decision people regret in week three.

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Not redoing SPF, DKIM and DMARC

Changing where mail originates without updating authentication records is how a business ends up in its customers' junk folders the week after a migration that otherwise went fine.

devices

Overlooking mobile devices

Every phone needs its account reconfigured. Twelve people at a laptop is fine; twelve people discovering it on Monday morning with no instructions is not.

Migration — common questions

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Will we lose any email during a Microsoft 365 migration?

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You should not, and the process is built so that nothing depends on a single moment. Mail is copied into the new tenant and verified against the source while your existing system stays live and authoritative. The MX switch happens only after that verification, and anything arriving during DNS propagation is picked up in a delta sync afterwards. The old mailboxes also stay available read-only for an agreed period, so there is a fallback.

help

How long does a migration to Microsoft 365 take?

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For 10 to 50 users from webmail or Google Workspace, typically one to three weeks end to end — most of it data copying and waiting on decisions rather than hands-on work. On-premise Exchange, very large mailboxes or a complex file structure take longer. The cutover itself is usually a single evening or weekend regardless of the total project length.

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What does not migrate to Microsoft 365?

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Email signatures, chat history, and most third-party app connections do not move and are rebuilt. Server-side rules and filters migrate inconsistently, so expect to redo the complicated ones. Distribution lists are recreated rather than copied, with membership verified with you. Everything else — mail, folders, contacts, calendars, files, shared mailboxes — moves.

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Can we migrate from Google Workspace to Microsoft 365?

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Yes, and it is our most common source. Gmail, Contacts and Calendar migrate well. The part that needs thought is files: Google Shared Drives and SharePoint sites do not map one to one, and deciding what becomes a SharePoint site against what becomes personal OneDrive is a structural decision worth making deliberately rather than by bulk copy.

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Can we run both systems during the transition?

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For a short period, yes, and for larger organisations a hybrid move, where mailboxes go across in batches, is often the right approach. It adds complexity in mail routing and calendar availability between the two systems, so we only recommend it where user count or risk genuinely warrants it. Below about 50 users, a single planned cutover is usually simpler and less disruptive.

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What about years of PST files on people's laptops?

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Those import into Exchange Online, and it is usually worth doing. A PST sitting on one laptop is one hard-drive failure away from gone, and it is invisible to any search or retention policy you put in place. Gathering them is often the slowest part of the project, because they are rarely where anybody thinks they are.

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Do you migrate businesses outside Kerala?

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Yes. Tech Geum is based in Kerala and works with businesses across India. Migration work is done remotely. Being in the same timezone matters more here than in most IT work, because the cutover and the week that follows are when you want someone answerable during your working hours rather than a global ticket queue.

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We are not sure Microsoft 365 is the right destination.

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Then it is worth settling that before the migration, not during it. We resell Microsoft 365, Google Workspace and Zoho, and our comparison of Microsoft 365 against Google Workspace sets out where each genuinely wins. Migrating twice is expensive and demoralising, and we would rather have the argument at the quoting stage.

Plan your Microsoft 365 migration

Tell us what you are moving from, how many mailboxes, and roughly how large they are. We will come back with a migration plan, a cutover window and a fixed-scope quote before anything is touched.

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    Data verified against the source before any switchover

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    Cutover scheduled around your trading hours

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    Old mailboxes kept readable for an agreed period afterwards

How long a move typically takes, and why institutions take longer, is on our page for Microsoft 365 partner in Thiruvananthapuram.

Prefer to talk first? Call +91 99467 89916 or email admin@techgeum.com.

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