fslogix: large ost corrupt at 50GB

Question

we have 1 user with an large Ost.
the ODFC vhdx is allowed to be 100 GB
we applied the regedit that the ost is allowed the be 100 GB with a warning at 90 GB
the moment the ost hits 50 GB the OST breaks.
I know that ost larger then 50 GB is not supported. Still i don’t see a reason for a hard cap at 50 GB.
I was wondering if this is fslogix related.
or if anyone can point me to the right direction.

Answer 1

Hello @thomas ,

Thanks for your query.

1.Is there any error message when the ost files corrupted?
2.What's your registry configuration of fslogix profile container and office container?
3.Did you enable the Cached Exchange Mode? If so, the maximum default size of an OST file is 50 GB, and An OST file will be 50-80% larger than what is stored in the mailbox. https://stealthpuppy.com/fslogix-containers-capacity/
https://learn.microsoft.com/en-us/outlook/troubleshoot/installation/cached-exchange-mode

WHY IS FSLOGIX O365 CONTAINER ESSENTIAL WHEN USING OFFICE 365? : https://virtualwarlock.net/why-is-fslogix-o365-container-essential-when-using-office-365/
Ongoing OST corruption with cached Exchange mode in Outlook 365 : https://community.spiceworks.com/topic/2296194-ongoing-ost-corruption-with-cached-exchange-mode-in-outlook-365

Best regards,
Leila

---

If the Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Hello @thomas ,

How are things going there on this issue?
Please let me know if you would like further assistance.

Answer 3

Hello @thomas ,

We haven’t heard from you in a couple of days.
Is there any update from your side?