Signed messages are missing from search results in a shared mailbox

Question

We recently completed moving all user mailboxes to Exchange 2013 from Exchange 2010.  We also have a policy that disables the 'download shared mailboxes' option in Outlook as it cause .ost files to get cumbersome and cause performance problems.  This
means that shared mailboxes that users have open are all in 'Online' mode.  Since the move to 2013, when users search against a folder in a shared mailbox, the only items that are returned are unsigned messages.  Our customer base very frequently
signs email and these signed messages do not show up in results.  This was working in Exchange 2010 so our users are frustrated by the sudden inability to receive complete and accurate search results.
If they perform a search of their local mailbox, which is using Cached mode, they are searching against their local index and they can find signed messages.  But since the shared mailbox is not cached to their local system, they are relying on the Exchange
server index and it does not seem to be indexing any signed messages.
Does anyone know how to force Exchange 2013 to index signed messages?

Answer 1

try to perform the below steps and check if it works or else we need to wait till Exchange 2013 SP1 which they have planned to bring digital signature message in exchange
Outlook 2007
In Outlook 2007, follow these steps to verify that indexing is complete:
In Outlook, click Tools, Instant Search, and then click
Instant Search.
When the Microsoft Office Outlook dialog appears, you should see the following:
Outlook has finished indexing all of your items.
New items are indexed when they arrive.
0 items remaining in "Mailbox -<<var>username</var>>"
0 items remaining across all open mailboxes.
Outlook 2010 and Outlook 2013
In Outlook 2010 and Outlook 2013, follow these steps to verify that indexing is complete:
In Outlook, click in the Search box.
Click the Search tab, click Search Tools, and then click
Indexing Status.
When the Indexing Status dialog appears, you should see the following:
Outlook has finished indexing all of your items.
0 items remaining to be indexed.
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