Before considering the actual migration operation, let us consider some important terms and know what does IMAP and Shared mailboxes in Office 365 account mean.
What does IMAP stand for and what does it mean
IMAP stands for Internet Message Access Protocol. IMAP messages are accessed on the fly using an internet connection. The e-mails are not downloaded or stored on the user PC. The user connects to the mail server using a browser and can view all the mails received. It is device independent and the mails can be accessed from any device. An other advantage of IMAP is that the mails are not automatically erased from the server unless they are explicitly deleted. Some examples of popular IMAP services are GMail, Yahoo, Hotmail, Outlook, GMX etc.
What are Shared mailboxes
Shared mailboxes are the mailboxes which are common to multiple users. Unlike folders, they are created with a separate e-mail address. Mails can be sent to and received from this address. For teams working on common projects or areas, this becomes particularly useful as there is no need to create individual mailboxes with different user-names and passwords. Shared mailbox is simply shared among different users within their own mailbox like a shared folder. For instance, a shared mailbox can be used by a marketing team to view and reply to the incoming mails to that mailbox. Important mails from the respective clients pertaining to the marketing team can be received in this shared mailbox whereas other mails are delivered to the usual address. Shared mailboxes may also include company information, other documents related to the organization etc. They are also permit access to common calendar entries to all members, allows multiple users to schedule and view tasks related to calendar.
How to create shared Mailbox and add members in Office 365
- Click on the link https://www.office.com/ and login using your admin account
- Click the six symboled App launcher icon
- Click on ‘Admin’ to go to the ‘Admin center’.
- Go to ‘Groups’, there you will get ‘Shared Mailboxes’.
Choose Groups > Shared mailboxes in the left pane. A list of existing shared mailboxes will appear. Click ‘Add a mailbox’.
- Here, you can specify the displayed name and email address of the new shared mailbox. Fill both fields and click the ‘Add‘ button.
- The newly created mailbox should appear on the list. Now highlight the mailbox and Edit the members section.
- Click the Members ‘Edit‘ button as shown below.
- Now, Click the ‘Add Members‘ button
- Choose the members, you can select the members who will have access to this Shared Mailbox. Click the ‘Save‘ button. In the image below user01-user04 have access to the shared mailbox.
How to perform migration of IMAP to Shared mailbox using EdbMails
EdbMails IMAP migration tool is an easy solution to migrate mailbox items from IMAP server to target servers. You can migrate mailboxes from most of the IMAP enabled mail servers such as Zimbra, Icewrap, Hotmail, Yahoo, G-suite etc. You can migrate IMAP selected mailbox items by applying various filters such as After Date, Before Date, From Address, To Address, Subject, Attachments name, Cc Address, Bcc Address etc.
This article guides you with a step-by-step procedure to migrate mailbox items from source IMAP server to the target Office 365 Shared mailbox.
Step 1: Download and install the latest version of EdbMails application from the website https://www.edbmails.com/pages/download.html. 
Step 2: Click on ‘Login‘ or ‘Start Your Free Trial‘.
To access the services from EdbMails application, you have to login to the application with your registered e-mail address or you can use a free trial version. 
Step 3: Select the option ‘IMAP Migration’ from the drop-down list.
Step 4: Connect to source IMAP server
There are two ways to connect to your IMAP server account
- Connect IMAP Single server
- Connect IMAP Multiple server
Connect IMAP Single server
Select ‘Single Server’, select ‘Connect to IMAP’ and choose the host name from the drop down list. In the drop down, you have options to choose from Outlook, Hotmail, Yahoo etc. You need to enter required credentials then click on ‘Login’ at the bottom.
Connect IMAP Multiple server
Here you need to select the option ‘Multiple server’ and ‘connect to IMAP’. Then click on ‘Load Mailboxes From CSV File’ and ‘Continue’.
If you don’t have a CSV file prepared beforehand, you can do that manually by downloading a sample CSV file and add the multiple mailboxes details as requested. Browse the CSV file to upload the modified CSV data back.
Now you can see list of mailboxes loaded by the application from the CSV file.
Step 5: Select the required Mailbox(es) from the list for migration and click on ‘Migrate To Office 365’ button to continue.
Step 6: Connect to destination Office 365 Admin account
You need to use Global Admin account for login. You are migrating items to the shared Mailbox so place a check-mark on ‘Connect to Mailbox(es)’ option and click ‘Next’.
Step 7: In this login wizard, you have to login with your organizational account. Enter the login credentials of the admin account and click on ‘Login’ at the bottom to continue the process.
After successful login, you will get a message box to ‘Load Mailboxes’ with 3 options. Select one of them. Mapping mailboxes can be done in 3 different ways. Here you can load mailboxes automatically or you can load using .CSV file and also it is possible to load mailboxes from previously stored list.
Step 8: After choosing the appropriate option, you will get list of mailboxes. It is important to select the shared mailbox account which you created earlier because you are migrating data from source to the Shared mailbox. Then click on ‘Continue’ at the bottom.
Step 9: Set the action as ‘Migrate’, select the mailbox on the target server and click on ‘Continue’ button at the bottom to start the migration process.
After completing all the above steps, you can see this wizard. During migration you can view the log and also you can stop the migration operation by clicking on ‘Stop’ button. You can also view the detailed migration operation after completion of migration process.
Conclusion: Shared mailbox is very practical when teams need to interact on a common agenda. You can migrate your IMAP data to your destination Office 365 Shared mailbox by using EdbMails tool and following these steps as listed above.
For more information please visit: https://www.edbmails.com/pages/imap-to-office-365-migration.html