Query about exchange online stubs

  • 11 November 2021
  • 6 replies

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At first, thank you for taking the time to read this query.

Currently we are facing a challenge where we want to rehydrate our exchange archive, which is located in Exchange Online.

We have a bunch of users, and not all data has been stubbed by a long shot.

So ideally we want to initiate a full restore of all mail items to rehydrate the archive, but we want to only overwrite the stubs, not the still present emails, because that would be a huge waste of time and resources.


I have attempted to save the restore as a script, as such making a ‘restore only if stub’ parameter available, but this does not seem to have the desired effect anymore, still all mails got restored.


Is there any such way to achieve this in CV currently? A way to only overwrite an email if it is a stub to avoid unneeded restores for items that already exist?


Thank you in advance.



Best answer by Scott Reynolds 6 December 2021, 20:06

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Userlevel 7
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Hi @WR1 !

I spoke to some of our Exchange experts and they advised that you should have hydrated before moving the mailbox.  

Their suggested was moving them back, hydrating, then moving them to the cloud.

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Hi @Mike Struening 

Thank you so much for your quick response.

I understand that with the current options, moving them back and re-hydrating would be the way to go if we only want to overwrite stubs at this time. (It is common knowledge that the recallmailbox tool does not work for o365 and generally stubs should be recalled prior to a migration) so I understand this, however that too could turn out to be a rather time consuming process, potentially requiring more effort than a full restore.


What I am curious about is whether or not this is by a limitation on microsoft/o365 side or if it could actually prove beneficial to open a ticket with support and propose a CMR for a feature that would allow to only overwrite stubs in o365.


Could you comment on the above?

Thank you kindly in advance.


Userlevel 7
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Sort of both.  0365 has to use ews and cvrecall can only use mapi.

I don’t know if there are plans to expand this in the future, but for now, it’s basically a MSFT limitation that we can’t worth with (today).



Userlevel 6
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@WR1 Is there any reason you cannot leverage the browse and restore? This is ideal over using the cvrecall tool. You can also filter with just stubs in the browse or skip existing messages.

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Hi @Scott Reynolds Thank you for your reply.
I double checked on your suggestion, and overall that could be utilized to only restore stubs I agree. (If the browse overview was equal to the live mailbox view)

So now what we are noticing is that not all the message types are up to date in CV.

So we have example mailbox A

Has definitely got x amount of stubs in the live mailbox

in CV browse shows 0 stubs, the email items are known and have been backed up, but they are not recognized as stubs, as such they do not show up on our ‘Find’ action.

Is there any procedure in order to basically do a re-scan of the mailbox to let CV know the updated message types?

If we can be sure the correct message types are shown, we would be able to utilize the find, then select all, and only overwrite stubs.

Also thank you @Mike Struening for the information.

Thank you in advance for your reply.


Userlevel 6
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Is is possible that you were performing backups with another agent, perhaps with another mailbox agent client? For example you were running V1 mailbox agent then migrated over to V2 or you installed the mailbox agent on another client and starting running mailbox backups at that location?

Taking a stub item, are you able to see it in the browse at all? Does it show it as a mail item instead of stub? Did you archive these mailboxes before migrating to o365?

If these do not help you should probably open a case and support and assist.