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What Should You do with Inactive User Data When You Migrate to Microsoft 365?
Well, from a Microsoft perspective, it’s a simple case of shifting all those inactive users to your shiny new environment to become Microsoft 365 inactive mailboxes. Sounds good, right? But let’s look at what that entails before you get too excited…
A License to Kill (Your IT Budget)
To move an inactive user to Microsoft 365, you need an active, licensed Microsoft 365 mailbox to migrate the data to. Once migrated, you can then place that newly created Microsoft 365 mailbox on legal hold, delete the user account, and redeploy the license for an active user (or use it to migrate another inactive mailbox).
It seems simple so far, but just wait…
Let’s take the example of Lancashire & McCoy, a fictional law firm migrating to Microsoft 365 that, for the sake of brevity, we’ll refer to as L&M from now on.
L&M has historical email data for 10,000 active users and 20,000 inactive users stored in a legacy archive. To remain compliant, cater to employees who might return (and keep the math simple), they need to retain all of their inactive user data.
They’ve bought licenses for the 10,000 active users they need, plus a surplus of 1000 licenses to cover future hires. However, they now discover (like you just did) that in order to move their 20,000 inactive users to Microsoft 365, they need to buy an additional 20,000 licenses just for the purpose of migration. That’s an expensive outlay and, even with the massive growth they’re expecting, they’re never going to need that many extra licenses available – meaning most of their investment will be wasted.
Batches Bog Down Migrations
Of course, being a savvy bunch of legal eagles, L&M don’t want to spend that much on additional licenses. Instead, the migration team hatches a cunning plan to overcome the Microsoft 365 inactive mailbox cost. They’ll use their 1000 surplus licenses to migrate their inactive users in 20 batches. Problem solved!
Not quite.
You see, the seemingly simple ‘recycling’ of an Microsoft 365 license takes 90 days by default. That means L&M have to wait three months between each batch of 1000 inactive users they migrate. In other words, they either have to take the hit on 20,000 extra licenses or add five years to their migration schedule.
Bigger Isn't Always Better
Even worse, with a 100Gb limit on Microsoft 365 mailboxes, migrating large volumes of data brings further delays. While they expected their Microsoft 365 mailboxes to auto expand immediately, at around 90Gb, the mailboxes no longer accept data until space has been made available by Microsoft. This takes between two weeks and a month to happen, further slowing the migration process.
Legacy Archive Vendors Don't Want You to Leave
To add insult to injury, L&M’s current archive vendor has already told them that converting the inactive user files from the proprietary format they’re stored in and preparing them for migration will take at least a year and cost a great deal for the “reconversion processing.” They even go so far as to claim (without a hint of bias) that it isn’t worth the hassle of migrating and suggest L&M remain where they are. At this point, L&M are starting to think that would be the better choice too.
Inactive Mailbox Migration Madness
Rather helpfully, for the purposes of our explanation, Lancashire & McCoy ran into both of these issues when they finally got all their inactive users migrated. Let’s see how it worked out for them…
With 20,000 inactive users slowly migrated to their Microsoft 365 environment, L&M decided to place all of them within a single, convenient, and free shared mailbox. But that didn’t work. With a 50Gb limit on free shared mailboxes, they were forced to create many of them to cater for the number of inactive users they had. Then, as fate would have it, their legal team opened a case a few weeks later requiring information regarding one of their departed employees. Identifying which shared mailbox that employee’s data was in took time, given how many there were to choose from.
When they finally identified the right shared mailbox, they tried to place that mailbox on legal hold, but that didn’t work either. As a free mailbox, the shared mailbox can’t be controlled by Compliance Center. This caused the L&M General Counsel to begin experiencing sleepless nights fearing spoilation claims.
A search for the user’s name within the shared mailbox also didn’t work because, as we highlighted before, the shared mailbox was now the owner of the data, not the inactive user. This meant finding information became far harder, with searches having to be carried out using the To and From fields or as full-text searches based on a specific SMTP address.
And, to cap it all off, the huge volume of inactive users in the L&M Microsoft 365 environment meant search performance was beyond sluggish. Deadlines for legal requests were missed due to delays identifying where to run the search and then because of the glacial pace of the search itself. L&M’s seemingly simple migration had become a legal, compliance, and technological nightmare overnight.
Inactive Users and Microsoft 365 Migration Challenges
- An Microsoft 365 license is required to migrate each inactive user
- A pause of up to 90 days is required before licenses can be reallocated, making batch migrations slower
- Using shared mailboxes introduces data volume limits and makes searching and eDiscovery more difficult
- Large amounts of inactive user data can degrade search performance in Microsoft 365
- Legal holds can’t be placed on shared mailboxes
- Migrating large mailboxes may trigger auto-expansion in Microsoft 365 mailboxes, which can cause a delay of 14-28 days
What Would L&M's Migration Have Looked Like if They had Chosen Archive360?
Now let’s take a look at the migration process L&M could have had. For starters, data would have been uploaded into Azure in just two days without any need for batch migration or delays waiting for licenses to be repurposed. Any issues and delays relating to their legacy archive vendor’s proprietary file format would also have been avoided, with Archive360 extracting files directly from the archive’s data layer, avoiding reconversion time and cost or the risk of leaving data behind.
The data would also have been classified and available for searching right away. At this point, L&M could have easily picked which users they wanted to migrate to Office 365 and left the static, legacy inactive data behind in Azure without any fear that important data had been lost. Not only would this approach have avoided a great deal of complexity and high license costs, but it would also have taken a fraction of the time – a matter of days versus several years.
Migration Challenges
Archive Migrations: Inactive users and Microsoft 365
One of the issues most organizations run into during an archive migration is inactive users and what to do with their data. In this short video, we discuss the challenges of inactive user data and how Archive360 can mitigate those challenges.
