Exchange 2013 "LastmodifiedTime" mailbox attribute - how to make sense of it?


When exporting data to a CSV file from the ECP, I am dumbfounded by the "LastModifiedTime" attribute. I would be expecting that the date/time would be very recent for all the active mailboxes, yet I see users who have that attribute dating back one or two days, and even more in some cases...

I know that for example "LastLogonTime" as relating to AD accounts is very fuzzy on the specific date/time (there is a random element), so is it the same with the "LastModifiedTime" for mailboxes? My gut reaction is that it should at the minimum match the LastLogon or LastLogOff attributes as can be obtained via PowerShell...

I also cannot find any articles from MS describing exactly what this attribute stands for and what actions of the user affect is.

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Raheman M. AbdulSenior Infrastructure Support Analyst & Systems DeveloperCommented:
it is the Last modified time of an item.
More details;
rr2rAuthor Commented:
Thank you, but I believe that the link you provided (which I also found before) is not specific to Exchange.

I think that the "Last Modified Time" must be updated based on some Exchange actions, and not be necessarily user-triggered? I am checking several accounts now and for all of them the logon/logoff time stamps do not match the modified time.

Just FYI - I am getting the "Last Modified Time" when exporting mailbox data to a CSV files via GUI - this is one of the columns available from the menu in ECP, but it does not show up in the "Get-MailboxStatistics" output via PowerShell....
Raheman M. AbdulSenior Infrastructure Support Analyst & Systems DeveloperCommented:
The link clearly states at the first few lines that it applies to exchange 2013.
Double check please
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rr2rAuthor Commented:
Indeed, but it does not offer any explanation to the root of my question - what is the difference (and why those are not the same), between the LastModified and LastLoggedOn time stamps for mailboxes. Judging from the dates, not even receiving a new message updates the "Modified" part, so what actions on the mailbox modify the attribute?
rr2rAuthor Commented:
More testing - receiving, reading, sending emails does not seem to update it. Neither does archiving on the mailbox - all actions that I would think "modify the item" as per article linked...
rr2rAuthor Commented:
Here is a similar question here on the forums: LINK
Raheman M. AbdulSenior Infrastructure Support Analyst & Systems DeveloperCommented:
LastLogontime indicates when the the user last connected to the mailbox.
LastModifiedTime indicates when the item is last modified.
From your comments I can see that the items are not modifying the "LastModifiedTime" attribute as it should.

Try to use Get-Message cmdlet and see if you can see the LastModifiedTime property with the updated information for that message
rr2rAuthor Commented:
Get-MailboxStatistics -identity "name" | fl does not have "Last Modified Time" at all.
Get-MailboxStatistics -identity "name" | select LastModifiedTime is blank so I imagine is not a valid entry.

I am not sure where are we going with the Get-Message command - I am trying to find out when (what conditions) the entire mailbox is marked as "modified" not a particular message inside.
rr2rAuthor Commented:
Got a case with Microsoft on this topic. Apparently, there is no documentation on this very topic and the person I was working with was not able to provide me specific answers.

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rr2rAuthor Commented:
There was no resolution. We can close this topic as not resolved.
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