We are excited to announce the general availability of Exchange Server Subscription Edition (SE). This release continues Microsoft’s long tradition of enabling customers to provide enterprise email s...
Updated Aug 06, 2025
Version 5.0
Blog Post
Just to leave a warning here for everyone considering to install Exchange SE on Windows Server 2025 to migrate over:
There is a critical ReFS (the filesystem being recommended for Databases & Logs) Bug right now in Windows Server 2025 Microsoft is working on.
It get's triggered as Volume utilization goes up naturally as you migrate mailboxes and finally the volume access gets slower and slower. Exchange Service turning crazy and you end up with Dismounted / Disconnected Databases as the Exchange Services are also unable to access the DB's / Logs anymore. Microsoft is aware of this issue and working on it, but the fix isn't published yet. You don't want to end up in that situation at the end of your migration.
Thanks for the information. Do you have any further information about the bug? KBArticle, etc.?
No public KB from MS available on this, but here's a public article speaking about this issue as well: https://borncity.com/win/2025/07/07/refs-file-system-fix-for-cpu-ram-utilization-bug-in-windows-server-2025-in-august-2025/
Did leave a post here as it seems nobody stumbled into this with Exchange (yet) besides us