Microsoft Exchange Server – Certificate Replacement

The time of on-premise Microsoft Exchange servers is beginning to draw to a close, although the Microsoft Exchange Server SE will continue, its feature complete essentially as of Exchange Server 2019, although there may be the odd minor changes here and there. Based on that replacing the certificate is a common task, the following instructions … Read more

Free/Busy Troubleshooting (November 2025)

Investigation into the loss of Rich Hybrid features for on-premise mailbox users, from around the beginning of November 2025. Exchange Version Says we need Exchange Server 2016 CU23 with April 2025 HU 15.1.2507.55, we are currently running 15.1.2507.58, so a later version than the minimum requirement, thus we are good on this version. Identified Issue … Read more

Install and Use Microsoft Exchange Online PowerShell Modules (Developer Machine)

The document provides a simple guide to how to install and use the Microsoft Exchange Online PowerShell modules to interact with Microsoft 365 infrastructure for the purposes of administering the Microsoft 365 infrastructure and applications; i.e. how to setup your Developer Machine. You may be able to install modules without administrative rights by adding the … Read more

Microsoft Exchange On-Premise Management Tools – Microsoft Windows 10 Installation

Late to the game, but here’s how you do it. To manage the on-premise Exchange Servers from your workstation, you can use the following procedure to setup these tools for use on your workstation. 1. You will need to install Microsoft Visual C++ 2012 Redistributable (x64): https://www.microsoft.com/download/details.aspx?id=30679 2. Then install these Windows Optional Features: Reboot machine, … Read more

FYDIBOHF23SPDLT

Even after designing, deploying and supporting Microsoft Exchange servers for longer than I choose to remember, I stumbled across something I never knew before yesterday; and that was why something was named the way it was. In Exchange 2007, Microsoft decided to remove the concept of “Administrative Groups”, however they needed to retain administrative groups … Read more

Microsoft 365 Exchange Online Mailbox Created Before Being Created in On-Premise Exchange

So you created an Exchange Online User and Mailbox but you’re still in a hybrid configuration where you are managing Exchange mailboxes on-premise. What this means is that the on-premise Exchange Organisation has no idea that the user exists, it doesn’t appear in Exchange Admin Center and it also probably won’t appear in the GAL. … Read more

Microsoft Exchange Poison Queue

The Microsoft Exchange Poison Queue is a little known queue on an on-premise Microsoft Exchange Server, maybe I’ve been lucky, but I’ve only seen emails end up here once in my time using Exchange Server which goes back to Exchange 5.5. However this week, we observed some messages going into the Poison Queue which were … Read more

Certificate Warning During or After a New Exchange Server Installation

During the preparation for a migration of the email service to Microsoft 365 Exchange Online, we were preparing a small test environment so we could step through what is required to faciltiate the links between Microsoft Active Directory, Microsoft Exchange on-premise and the Microsoft 365 cloud environment that includes Microsoft Exchange Online cloud hosted email.  … Read more