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Successfully migrating to Microsoft Office 365 

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The migration of Microsoft Office 365 within a company’s IT infrastructure is a process that must be taken seriously. Indeed, the deployment of this platform can be accompanied by unpleasant surprises, which can compromise data security.  Therefore a good planning of procedures is essential during a migration to Office 365. Here are our recommendations to follow to ensure a successful migration to Microsoft Office 365.



The pre-migration stage is the one that provides the opportunity to plan the process well in order to avoid the nightmare of migration. In fact, good planning of a migration process is 80% of the work done. To do so, we strongly recommend that you consider the following steps:

Define your organization’s needs in terms of Office products

A good assessment of the business needs for Office applications is the first step to accomplish: e.g. Email (online exchange), document sharing (OneDrive, SharePoint), communication (Teams, Skype for business). This step is the anchor point to have a better overview of the migration phases that will be determined under the chosen support.

Evaluate the capabilities of the current infrastructure

In order to support data transfer to a Cloud Office 365 environment, it is necessary to obtain the best diagnosis on the state of the current infrastructure. This transparency will help guide decisions on the maneuvers to be performed for optimal migration. At the same time, this step allows the new environment to be modulated according to the volume of data that can be transferred.

Produce an inventory of the data to be transferred 

Verification of resources and data to ensure the choice of an infrastructure that suits the needs of the organization :

  • Identifying and cleaning up user accounts;
  • Collect the size and number of mailboxes;
  • Make a list of groups and aliases;
  • List the domain names involved in the migration;
  • Document as much information as possible about network settings; proxy and/or firewall configuration, DNS hosts, Internet connection, etc.
  • Target the information found on all intranet sites selected for migration;
  • Gather detailed information on applications that are integrated with existing systems (messaging applications, workflow, CRM and so on).
  • Review the list of user locations if there are multiple sites.

Select the optimal type of migration: hybrid or failover 

Just before the migration stage, it is essential to determine the appropriate type of migration defined according to: the email system, the type of hosting desired (full or partial), the number of users to be migrated and the speed at which the complete migration must be produced. The most frequently deployed migrations are:

  • A hybrid deployment extends the range of functionality and administrative governance established within the existing local Microsoft Exchange organization to the cloud. This technique is often used because it provides secure message transfer, shared calendar availability information, and message tracking between local organizations and Exchange Online.
  • A failover Exchange migration is most recommended for architectures that are moving towards 100% cloud-free data management. In addition, it is recommended for organizations with a mailbox inventory between 150 and 2000. However, the local server must have a certificate issued by a trusted Certificate Authority and a public IP address, as it must connect to a local Exchange server to migrate by failover.



Preparing the local architecture (Active directory) 

In a migration plan, where it is important to maintain a local architecture, it is essential to configure AD synchronization tools adapted to the company’s IT environment.

Deploy customized security policies 

IT administrators need to set up a system of audits, reports and real-time change alerts during the migration process to ensure data security so they can keep an eye on: access, legal retention requirements and anomalies during data transit.

A 3-phase migration is strongly recommended: 1) Email (Exchange), 2) Communication tools (Team-Skype), 3) Data (SharePoint-OneDrive). This three-sequence procedure allows :

  • Minimize the impact of the migration on daily operations ;
  • Facilitate staff integration and learning;
  • Simplify implementation within the network.


Creating a new DNS record 

This step will facilitate the process of connecting users to their respective Office 365 mailboxes. Once all mailboxes have been migrated, it is possible to set up a DNS record for automatic discovery. For organizations that have kept a local Exchange structure, it will be important to point the CNAME DNS record to Office 365.

Disabling local Exchange servers

Before proceeding with this last step, it is very important to ensure that all messages have been redirected to the Office 365 mailboxes; otherwise, it will be impossible to recover none transferred data.

Stabilizing the migration

Of course, any change brings a lot of insecurity within an organization. Once the business environment is officially administered by Office 365, it is very important to plan an adaptation period with your technical assistance. In addition, in order to optimize the new Office 365 environment within your organization, the involvement of a few players familiar with this new Office 365 platform will ensure continuous training and the proper functioning of the various programs used within the company.

 Mandating an external firm: expense or investment?

The fact remains that a migration is specific to each company and the importance of properly organizing the implementation of Office 365 is often the issue that will define the appreciation of this new platform within your work team. Experienced technical assistance often makes the difference in the level of risk attributable to the costs and unforeseen events involved in this type of migration. The rapid intervention of an external firm will help maximize the investment of an implementation of this scale.

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