I've been in my new job for about six months, and one of the major tasks ahead is moving away from Mimecast to fully utilize the security and archiving capabilities of our Microsoft 365 E5 plan. I'm looking for insights from anyone who has already made this transition. Specifically, what challenges should I anticipate when transferring archives from Mimecast to Microsoft 365?
We hadn't set up retention policies in Microsoft 365, so we'll need to ensure all current archives are ported over to retain our email history. Additionally, could anyone recommend vendors or partners for this migration? I've come across a vendor named Transvault that specializes in this kind of service, but I'm curious about other options. Finally, any advice on establishing retention policies in Microsoft 365 would be greatly appreciated. I'm a bit anxious about how to purge old emails without accidentally deleting important messages from user mailboxes.
2 Answers
Is your Mimecast setup cloud-based? I’m curious why you’re dropping it?
You'll find plenty of managed service providers (MSPs) or consultants who can help with the migration. Just keep in mind that the archiving features in Mimecast differ from what you get with Microsoft 365's archiving. After making the switch, consider implementing a third-party backup solution, like Veeam for 365 or Dropsuite, since having a robust backup strategy post-migration is crucial.
Regarding retention policies, there really isn’t a one-size-fits-all approach. It’s important to align these policies with your company's overall document retention strategy, especially concerning legal matters.
We already use Commvault for traditional backups, so that’s something. I know Mimecast's archives and Microsoft 365's archiving aren’t the same, and we're working on mapping our Mimecast retention to the new policies in Microsoft 365. The idea is to export each mailbox from Mimecast and import it into the corresponding online archive. If we end up with duplicate emails, we’ll deal with it, but we want to make sure all relevant emails are captured and retained. It would be awesome if migration software could de-duplicate messages during the transfer, but I suspect that's rare.
It's just Mimecast; I think 'cloud integrated' refers to a different product. We’re switching because it costs us around $200k, and since our E5 licenses cover email security and archiving/retention, we don’t see a reason to pay double for similar functionality.