I’m sure that a lot of people have seen this issue before when migrating to Exchange Online:
The BadItemLimit was exceeded and therefore the move request failed.
A while a go Ben Winzenz wrote an excellent post on the You Had Me At EHLO blog, where he mentioned that there was a change in Exchange Online and now failed mapping of SIDs will count towards the BadItemLimit.
So far so good, but how do we solve such issues when increasing of bad item limit is not an option and you have to migrate approx. 130.000 mailboxes?
When it comes to Exchange Online migration and you have a lot of SMTP namespace, you might run into issues
- when you’re trying to migrate the user
- when you try to grant Send As permissions
I spent last weeks quite some time with Outlook performance issues in an Exchange Hybrid scenario. In addition this is not a normal Hybrid as here multiple Exchange Organizations from different AD Forests without any Trust Relationships are involved.
Thus I’m not talking about the scenario described in TechNet Multi-forest hybrid deployment scenario. It looks more like this:
Currently I’m upgrading an Exchange 2013 environment to Exchange 2016. In general this upgrade runs very smoothly and is almost seemless for user. It’s a complete different story when you’re coming from Exchange 2010.
So far I got only positive feedback and no issue were reported. Until a bunch of shared mailbox have been migrated.
Users complained they cannot access these mailbox anymore. First I couldn’t reproduce the issue, until I got another important detail:
All these user are using Outlook for Mac and indeed I could reproduce the behavior.
This issue is fixed in version 15.38 (170815) of the Insider Fast Build as of August, 16:
During a migration to Exchange 2013 several users started complaining about intermediate connectivity issues.
After some investigation I still had no clear picture of the issue. The users had in general no connectivity problems, but they got sometimes errors (e.g.: failed authentication, request could not be completed). And this not in a consistent way.
Some reported issues in Outlook and some on a mobile device using an app. When I heard about the mobile apps, my first thought was maybe an Exchange ActiveSync issue. But the apps on the mobile devices were using EWS.
A few weeks ago I was involved in a migration project. At one point in time we needed a script to retrieve permissions on mailboxes on folder-level. Besides this we needed to read the property PR_NT_SECURITY_DESCRIPTOR for folders.
Why we needed to read the property PR_NT_SECURITY_DESCRIPTOR?
Read more about in this article here!
Now back to the script. I know there are many scripts out there, which are doing this job. But we needed something to get the data real quick and a way to retrieve SIDs. I started looking for all options and ended in .NET mutlithreading for the first and MrMAPI for the second need.
This post is about my personal journey with a cross-forest migration.
When it comes to account migration there is no way to do so without sIDHistory. It would be really hard to have a smooth migration without.
By using this attribute a end-user most likely won’t experience any impact…..unless you start doing a cleanup of this attribute.
In terms of Exchange users might see something like this
But what’s behind those issues and how could you mitigate this? I was part of a migration, where those issues popped up and I’m going to describe how you could determine possible impact for end-users before it happens.