MailboxExportRequest ContentFilter is "Received -ne $null" when querying by date
Solution 1:
It's a finicky syntax error and made worse by incorrect/unclear documentation. Please try the following --
$y = ((get-date).addDays(-1)).ToShortDateString()
$exportRequest = New-MailboxExportRequest -ContentFilter "Received -lt '$y'" -mailbox userID -FilePath \\SHARED\folder\userID.pst