Details
Because Outlook defaults to archiving messages to the hard drive of the local machine where it runs, this option was turned off for the Dartmouth environment. You will need to run this process manually to remove old items from your account.
One exception to this is the Deleted Items folder. For this folder in particular, you can configure Outlook 2016 (Windows) to automatically delete those messages every time you exit Outlook. To do this, select File from the Menu bar, then Options. Click Advanced in the left column. Under the Outlook Start & Exit section place a check in the Empty Deleted Items folders when exiting Outlook box to have your trash emptied every time you exit Outlook.
In Outlook 2016 (Mac) you can manually empty trash by holding down the Control key and then clicking Trash in the folder list. Click Empty Folder.
Warning: Following the procedure below will delete email, calendar, tasks, to do, and journal items from your account on the Dartmouth servers. After you run this process, the data deleted will only be available from the file you created.
To remove older messages from your account in Outlook 2016 (Windows), click File in the Menu bar, next click the Cleanup Tools button, then Archive. Select the folder from which you want to remove older messages; select Mailbox - First M. Last if you want to archive everything in your account prior to a specific date. In the Archive items older than field, enter the date prior to which you want all items in the folders selected to be copied to an archive file on the hard drive on the computer you are using. Next, in the Archive file field, browse to where you want this archive file created.
WARNING: You don't get a second chance at this. Once you know all the settings are correct, click OK. The archive process will begin immediately. A copy of everything that is archived will be placed in a file on the hard drive on the computer you are running it from.
To remove messages from your account in Outlook 2016 (Mac), it's all or nothing; you're not able to select a subset of your e-mail. You can archive the existing files and then delete the older files you don't need in your normal mailbox. From the File menu, click Export. Select the kind of export you want. Outlook exports Outlook Data File format as .olm files. Check the item types you want to include in the export, and then click Continue. Enter a name for the archive file and a location to store it, and then click Save.
In Apple Mail select the folder you wish to archive, click the menu item Mailbox then click Export Mailbox. Choose the location you wish to save the mailbox file containing your archived mail. This will create a complete copy of the folder you selected.