Enabling Outlook Cached Mode with FSLogix breaks Outlook

Question

I'm trying to get FSLogix working properly in a test environment prior to use in production.

During testing I'm able to consistently reproduce the following:

1. FSLogix with Outlook online mode works.
2. FSLogix with Outlook cached mode does not work, Outlook will not open.

This is a follow up to a question a colleague submitted: https://learn.microsoft.com/en-us/answers/questions/385841/outlook-365-c2r-cannot-open-outlook-ost-cannot-be.html

This also seems related to: https://learn.microsoft.com/en-us/answers/questions/193767/ost-file-is-not-created-in-vhdx-container.html

Details of environment:

• Windows Server 2019 (1809), all updates installed
• RDSH Collection Session Host (Session Host only, Broker and Gateway are on other systems)
• Office 365 Apps for Enterprise (MonthlyEnterprise Channel) deployed using ODT with Shared User Licensing
• FSLogix 2.9.7838.44263
• Profile Container and Office Container both enabled

HKCU\software\policies\microsoft\office\16.0\outlook\ost\NoOST Set to 2
^ Set after reading: https://www.vcloudinfo.com/2021/06/how-to-implement-outlook-cached-mode-with-fslogix-profiles.html

With HKLM\Software\Policies\FSLogix\ODFC\outlookcachedMode DISABLED, Outlook opens in online mode and seems to work fine.

With HKLM\Software\Policies\FSLogix\ODFC\outlookcachedMode ENABLED, Outlook will no longer open. Screenshot of error message attached.

Note No local profile folder existed prior to this logon. OST is created in the default location when Outlook tries to open. Look at timestamp and system time.

I have figured out that looking in Computer\HKEY_LOCAL_MACHINE\SOFTWARE\FSLogix\Profiles\Sessions\<SID of User Session> after the user logs in shows that the OutlookCachedModeEnabled value only updates to 1 if the GPO for outlookcachedMode is set in BOTH:
**Computer Configuration\ Administrative Templates\ FSLogix\ Office 365 Containers**
AND
**Computer Configuration\ Administrative Templates\ FSLogix\ Profile Containers**

Here's the registry settings upon logon of the test user:

Answer 1

Thank you for the response, I meant to come back and update this post sooner. I found the cause of the issues.
Delprof2 was in use to clean up profiles, running frequently as a scheduled task. Delprof2 apparently does not play nicely with FSLogix. If Delprof2.exe runs while a user is logged in with an FSLogix profile it breaks Outlook.

Answer 2

I'm not sure if your config is the right one. I don't use that NoOST registry at all. I also don't use the set outlook cached mode on succesful container attach. I only use the Outlook policy itself (use cached mode for new and existing profiles).

I think you need to remove those FSLogix policies, since Outlook Search in Windows 2019 is per user now and managed by Windows, not FSLogix. The only thing you should do in FSLogix is enable the Office container that's it.

Answer 3

Saw the notes about 2019 search in the documentation when I first set this up.
Search is (has been) disabled in the GPO

I deleted the NoOST key.
Set the FSLogix GPO for Set Outlook cached mode on successful container attach back to disabled.
gpupdate /force, Deleted FSLogix Key from HKEY_LOCAL_MACHINE\SOFTWARE\ , repaired install, rebooted.

Pretty much the same results, usually get the same "You must connect to Exchange at least once before you can use your Outlook data file"

Sometimes Outlook will open on the first login (When Profile & ODFC VHDX are first created). And Cached mode is enabled, but then if I sign-out and login again to the same system then it's broken for good (until the VHDX files are deleted) This is the error:

Answer 4

I'm wondering if my problems are related to using both FSLogix Profile Containers and FSLogix Office 365 Containers.

I would have thought that when both were enabled it would just work, but reading through the docs again kind of makes it sound like Exclusions need to be added into the FSLogix Profile Container policy to exclude things that the FSLogix Office 365 Container is handling. Is that correct?

Answer 5

The documentation states that they can be used together:

Using Profile Container and Office Container together
There are several reasons why Profile Container and Office Container may be used together. The most common reasons are:

Discretion is wanted in the storage location for Office Data vs. other profile data
If the Office Container or Profile Container is damaged, the remaining data remains intact. Storage discretion is useful if there is a problem with Office Data, which can be recovered from the server as the Office Container can be deleted without impacting the rest of the user configuration.
Office Container may be used with Profile Container as a mechanism to specify which Office components will have their data included in the container

But doesn't give any complete instructions/examples on how to properly configure the use of both...

Right now I'm trying to get the redirections.xml working to exclude Outlook from the FSLogix Profile Container.