As with all previous versions of OWA, Exchange 2013 and Exchange 2016 has a search function that is above the mail column as seen below.
I came across an issue recently where if you did a search in OWA 2013, no results would be show, no matter what information I used as the search keywords. No matter what no search results where found. In Exchange 2013 , the search index is stored with the Mailbox store where the users are located. To resolve this issue and build the OWA 2013 or OWA 2016 and the Exchange search index again we needed to do the following. This error may also occur with Outlook clients that are not in cached mode.
In exchange RTM navigate to services stop the Microsoft Exchange Search service.In Exchange CU1 and CU2 stop both the Exchange Search services (Exchange Host Search and Exchange Search service) as well as the Search Host Controller . Once done locate the folder on your server where the Mailbox database is where the user is trying to search from. For example mine is here.
C:\Program Files >Microsoft > Exchange Server > V15 > Mailbox > Mailbox Database 1403936621 < Exchange 2013
C:\Program Files >Microsoft > Exchange Server > V16 > Mailbox > Mailbox Database xxxxxxxx < Exchange 2016
If you are unsure where the the mailbox database is use the command below from power-shell.
Get-MailboxDatabase "yourmailboxdatabase" |fl name,*path*
Once the path is located you will find a folder name with a long “GUID” and the word Single on the end.
Rename this folder .old.
We then need to start the Microsoft Exchange Search service again, The server will now begin to rebuild its search index.
Give it plenty of time to rebuild then issue the command below and make sure the status of Content Index Status is seen as healthy.
As seen below, if it says healthy try your search and you should see that your search results now appear in Outlook and OWA 2013.