Re: Exchanging stories
When we moved from Groupwise to Office365 two years ago, I discovered there was an ongoing bug with the Android email client. It seems that if it was using imap against a Groupwise GWIA, then every time it checked for new mail, it would put another copy of every single mail sent from that device into a "Sent" folder it created on the server, (not into the "Sent Items" folder that Groupwise uses). And if a user had multiple Android devices, yep, each of them would do that with whatever locally-sent emails they had. Every 5 or 10 minutes, all day and all night. So when I start doing the final GWCheck's before the migration (and am actually paying attention to something other than error messages and orphaned attachments), I noticed lots of accounts with 400,000+ messages to be migrated. Once I figured out what had happened, it took a while to figure out a way around it. Deleting those Sent folders was going to take forever since the GW client liked to barf at more than 5000 messages in a folder, and even trying to delete that many emails slowed the POAs to a crawl. To top it off, the migration software didn't seem to honor my request to skip any folders named "Sent". In the end, I just had to let the migration jobs run for months trying to get most of the stuff migrated over.
I don't ever want to migrate an email system again.