For those of you who have ever wished to see what it takes to build some of the more advanced scripts that i post on this blog as part of the Connections Online conference I put together the following talk http://videos.devconnections.com/product/Exchange-Management-Shell-Beyond-the-One-Liner,5789-3.aspx . While i cant promise that this will teach you to be a guru in 60 minutes hopefully it may present a few different idea's and methods you may not have considered before and allow you to bash out a few more of your own scripts. There are also a lot of great videos on various aspects of Exchange posted by other Exchange MVP's that are defiantly worth checking out http://videos.devconnections.com/catalog/Exchange,390.aspx
For the last couple of years the most constantly popular post by number of views on this blog has been Export calendar Items to a CSV file using EWS and Powershell closely followed by the contact exports scripts. It goes to show this is just a perennial issue that exists around Mail servers, I think the first VBS script I wrote to do this type of thing was late 90's against Exchange 5.5 using cdo 1.2. Now it's 2020 and if your running Office365 you should really be using the Microsoft Graph API to do this. So what I've done is create a PowerShell Module (and I made it a one file script for those that are more comfortable with that format) that's a port of the EWS script above that is so popular. This script uses the ADAL library for Modern Authentication (which if you grab the library from the PowerShell gallery will come down with the module). Most EWS properties map one to one with the Graph and the Graph actually provides better information on recurrences then...