When only specific content is desired in the PST file (or back into the mailbox), a common set of filters can be used to exclude the rest of the messages. Export or import to PST supports the following filters: Locale, StartDate, EndDate, ContentKeywords, SubjectKeywords, AttachmentFileNames, AllContentKeywords, SenderKeywords, and RecipientKeywords.

For example, to import only those messages that were created between 1/1/07 and 12/1/07 and contain the word "review" in the subject and any of the words {"project","alpha"} in the body, you need to enter the following command:

Import-mailbox -Identity john@contoso.com -PSTFolderPath D:\PSTs -StartDate 1/1/07 -EndDate 12/1/07 -SubjectKeywords:'review' -ContentKeywords:'project','alpha'