This is a quick one but definitely helpful:
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Utilize the -ResultSize Unlimited only when you are done formatting and testing your command. If you have a big Exchange environment, then this could potentially run long and eat up your resources.
A good way to test initially to see if your results are correct is by removing "-ResultSize Unlimited" and "Export-CSV H:\Code\ExchangeFWDlist.csv –NoTypeInformation" and adding "Select-Object -First 5".
Choose a small number for Select-Object so that the output returns quickly and does not create a resource utilization issue on your Exchange server.
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Get-Mailbox -ResultSize Unlimited | Select Name, Alias, ServerName, DeliverToMailboxAndForward | where {$_.DeliverToMailboxAndForward -eq "true"} | Export-CSV H:\Code\ExchangeFWDlist.csv –NoTypeInformation