Our M365 administrator changed the email retention policy to 7 years in our M365 tenant. Prior to this, there was no policy enforced.
The incremental backups prior would complete in under 30 min. for maybe a few GB of data. Directly after the change, there was 91 GB. The next was 177 GB, which I ended up killing, and then 240 GB that ran for almost 3 days before I killed it.
I found the one mailbox slowing things down which had a large amount of emails - not the biggest mailbox but just the amount of mail items.
My question is, what is the reason for the change after the Retention Policy is applied to email? It sounds like it may have to “re-seed” the data - what does this mean?
