Migrating to Microsoft 365 can be a meaningful change for many London SMBS, offering advanced collaboration tools, improved security, and increased productivity. However, without careful planning, the migration process can disrupt operations. With the help of reliable IT support services in London, this guide walks you through each migration stage, helping you achieve minimal downtime and maximum business continuity.
Pre-Migration Checklist
Preparing your environment before starting your migration is essential. A thorough pre-migration checklist helps prevent unexpected issues later.
Mailboxes:
• Perform an inventory of all mailboxes, including size, usage, and ownership.
• Clean up old or unused emails and archive essential data.
• Avoid losing essential email records by saving a full copy of mailbox data before migration.
Permissions:
• Audit all user, shared, and delegated mailbox permissions.
• Document calendar and folder sharing settings to replicate them after migration.
OneDrive:
• Review the contents of each OneDrive account and remove redundant files.
• Note all shared links and access permissions for reconfiguration later.
Handling Legacy Systems
Exchange 2013:
• Consider a hybrid migration approach to allow a staged transition.
• Ensure all security patches are applied, even if Exchange 2013 lacks mainstream support.
• Migrate user data gradually to minimise downtime and keep users operational.
SharePoint Server:
• Evaluate each site collection and its relevance to daily business operations.
• Plan to move only active or business-critical content to SharePoint Online.
• Rebuild custom workflows or integrations using Microsoft Power Platform, where necessary.
DNS Propagation Tips for MX and SRV Records
Correct DNS settings are crucial for a successful migration and uninterrupted services.
• Update MX records to point to Microsoft 365 once mail routing is ready to switch.
• Add SRV records for services like Teams and Skype for Business to function correctly.
• Reduce TTL (Time-To-Live) values before making DNS changes to help them propagate faster.
• Allow 24–72 hours for complete DNS propagation across all ISPS.
Common Issues and Troubleshooting
Even with planning, issues can arise. Here is how to address the most common problems during Microsoft 365 migration.
Autodiscover Problems:
• Symptoms include repeated Outlook login prompts and failed profile setups.
• Solutions include verifying DNS Autodiscover entries and clearing cached credentials.
• Use diagnostic tools to test connectivity and validate email profile settings.
Calendar Permissions:
• After migration, shared calendars may not display correctly.
• Reassign access manually or via PowerShell scripts in the Microsoft 365 admin centre.
Outlook Reauthentication:
• Users may be prompted to log in again due to modern authentication changes.
• Clear stored credentials and ensure modern authentication is enabled.
• Notify users beforehand to reduce confusion and support requests.
Choosing Your Migration Tool: Built-in vs Third-Party
London SMBS should assess their technical needs, migration complexity, and budget when selecting tools.
Microsoft Migration Manager:
• Fully integrated with the Microsoft 365 admin centre.
• Ideal for straightforward, small-scale migrations.
• Offers basic reporting and progress tracking.
Third-Party Solutions:
• Provide more flexibility for complex environments, including staged or cross-tenant migrations.
• Allow granular control over content, migration schedules, and error handling.
• Often include automation, rollback options, and advanced reporting tools.
• May incur additional costs, but can reduce the risk and effort of complex transitions.
Conclusion
Migrating to Microsoft 365 brings lasting benefits—enhanced collaboration, security, scalability, and cloud-native efficiency. By following a structured plan, preparing early, addressing legacy dependencies, and selecting the right tools, London SMBS can make this move confidently and with minimal disruption.
A successful migration does not happen by chance. It happens through expert guidance and reliable planning. IT support services in London are vital to ensuring a seamless Microsoft 365 transition, particularly when continuity, data protection, and timing are crucial.
Frequently Asked Questions
How much time is generally needed to migrate to Microsoft 365?
• It depends on the number of users and data volume. Small migrations might be completed over a weekend, while larger ones could span multiple weeks.
Can we avoid downtime during the migration?
• Yes, with hybrid strategies and careful planning, downtime can often be avoided or significantly reduced.
Will our existing email and calendar data be preserved?
• Yes, all key data, including emails, calendars, and contacts, can be migrated and retained during the transition.
Do users need to reconfigure Outlook after migration?
• Most users must restart Outlook and may be prompted to reauthenticate. Proper preparation makes this seamless.
Should staff be trained post-migration?
• While Microsoft 365 is user-friendly, training improves user confidence, reduces queries, and speeds up adoption.