Get my free assessment \u2192<\/a><\/div>\nWhat Changes for Outlook, Mobile Devices, and Shared Mailboxes?<\/h2>\n
Users need a new Outlook profile pointing at Microsoft 365, mobile devices need the new account added, and shared mailboxes, resources, and groups need to be recreated, but email addresses stay the same.<\/strong> A short welcome note covering these steps prevents most first-day support tickets.<\/p>\n\n- Outlook on the desktop.<\/strong> In Outlook, go to File, then Account Settings, then Manage Profiles. Remove the WorkMail account and add the Microsoft 365 account. Autodiscover detects the Exchange Online settings automatically.<\/li>\n
- Phones and tablets.<\/strong> Remove the old account and add the Microsoft 365 account in the Outlook mobile app or the device’s mail app.<\/li>\n
- Shared and resource mailboxes.<\/strong> Recreate them in the Exchange admin center and reassign permissions, since they don’t come across with IMAP.<\/li>\n
- Multi-factor authentication.<\/strong> Turn it on and walk users through registering, ideally before cutover so nobody is locked out on day one.<\/li>\n
- Signatures and rules.<\/strong> Ask users to recreate personal ones, or publish standard signatures centrally.<\/li>\n<\/ul>\n
How Long Does It Take, and When Should You Start?<\/h2>\n
A small organization can finish in about a week, while hundreds of mailboxes can take several weeks, so with support ending March 31, 2027, you should start now and aim to finish by early March.<\/strong> The table below is a planning estimate, not a Microsoft or AWS figure.<\/p>\n\n\n\nMailboxes<\/strong><\/th>\nTypical Project Length<\/strong><\/th>\n<\/tr>\n<\/thead>\n\n\n1 to 25<\/strong><\/td>\n| 3 to 7 days, including the 72-hour window<\/td>\n<\/tr>\n | \n25 to 150<\/strong><\/td>\n| 1 to 3 weeks, with a pilot and phased rollout<\/td>\n<\/tr>\n | \n150 to 500<\/strong><\/td>\n| 3 to 6 weeks, in parallel batches<\/td>\n<\/tr>\n | \n500+<\/strong><\/td>\n| 6 to 10 weeks or more<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n As of November 2026, you have roughly five months. A schedule that works for most organizations looks like this:<\/p>\n \n- November and December.<\/strong> Audit mailboxes, choose plans, license users, and run a pilot with a few mailboxes.<\/li>\n
- January and February.<\/strong> Migrate in waves, handle calendars and contacts, and run safety exports for every mailbox.<\/li>\n
- Early March.<\/strong> Finish cutover, validate, and keep a buffer for surprises.<\/li>\n
- The last two weeks.<\/strong> Treat them as contingency, not as planned working time. AWS has announced no extension.<\/li>\n<\/ul>\n
How Much Does the Move Cost?<\/h2>\nExchange Online Plan 1 lists at $4 per user per month on an annual term, the same as AWS’s listed WorkMail price, while Microsoft 365 Business Basic lists at $7 after Microsoft’s July 2026 increase from $6.<\/strong> Prices change, so confirm them at purchase.<\/p>\n\n- Amazon WorkMail.<\/strong> Listed by AWS at $4 per user per month with a 50 GB mailbox.<\/li>\n
- Exchange Online Plan 1.<\/strong> $4 per user per month on an annual term, with a 50 GB mailbox and no Teams or Office apps.<\/li>\n
- Exchange Online Plan 2.<\/strong> $8 per user per month, with a 100 GB mailbox and an archive.<\/li>\n
- Microsoft 365 Business Basic.<\/strong> $7 per user per month on an annual term, adding Teams, OneDrive, and SharePoint to the Exchange mailbox.<\/li>\n
- Migration labor.<\/strong> The one cost people forget. A do-it-yourself move costs admin time, and a managed move is quoted up front.<\/li>\n<\/ul>\n
What Are the Most Common WorkMail Migration Mistakes?<\/h2>\nThe most common mistakes are assuming IMAP moves everything, waiting too long, and switching mail flow or deleting the batch too early.<\/strong> Almost all of them are avoidable.<\/p>\n\n- Assuming IMAP carries calendars and contacts.<\/strong> It doesn’t, so users discover empty calendars on day one.<\/li>\n
- Expecting a PST export.<\/strong> AWS’s export is a MIME zip with email and calendar items only.<\/li>\n
- Planning around admin credentials.<\/strong> WorkMail IMAP migrations use each mailbox’s credentials, so collect or reset passwords in advance.<\/li>\n
- Leaving WorkMail retention policies on.<\/strong> Messages the policy deletes mid-project won’t migrate.<\/li>\n
- Blocking the migration with access rules.<\/strong> WorkMail access control rules can stop Microsoft’s service from connecting.<\/li>\n
- Deleting the batch too early.<\/strong> Mail sent to WorkMail afterward is never copied.<\/li>\n
- Forgetting DNS records.<\/strong> A missed SPF or DKIM record can send legitimate mail to spam.<\/li>\n
- Starting in February.<\/strong> There is no slack left if anything goes wrong, and AWS has not offered an extension.<\/li>\n<\/ul>\n
Should You Do It Yourself or Use a Managed Migration?<\/h2>\nDo it yourself when you have a small number of mailboxes, simple needs, and admin time to spare, and use a managed migration when you need calendars and contacts carried over, have many users, or can’t afford errors with a hard deadline looming.<\/strong><\/p>\n\n\n\nSituation<\/strong><\/th>\n | | | | | | | | |
![\"Timeline](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2026\/11\/workmail-shutdown-timeline.png\")
<\/p>\n![\"Chart](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2026\/11\/workmail-route-coverage.png\")
<\/p>\n![\"Diagram](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2026\/11\/workmail-imap-six-steps.png\")
<\/p>\n