Olminator as of v2.67 supports extracting email addresses from emails and calendar appointments (e.g. the sender's or any receivers' email addresses) and storing them aggregated (i.e. each unique email address shows up exactly once) and sorted alphabetically into a .CSV (Comma-Separated Values) file. You can then use Apple Number, Microsoft Excel or any other application capable of processing a .CSV file to further work with that data.
When Olminator introduced the Viewer tab allowing you to navigate the entire content of the selected .olm archive, it provided with a completely new and very convenient way to select subsets of items contained in your Microsoft Outlook for Mac export. Email address extraction now makes use of that fact:
To extract email addresses from your .olm file, open the Viewer tab in Olminator's navigation bar and browse the folders of your archive displayed to the left. Select the folder (e.g. an entire account, or "Emails" or "Calendar" or any sub-folder thereof) that you want to extract email addresses from. The "Start [extracting email addresses]" button at the button bar on the bottom of Olminator's window will be enabled, once you have a folder selected. Press that button to start the extraction process.
Alternatively, you can right-click a folder from the folder tree and select "Extract email addresses" from the popup-menu.
Olminator will extract all email addresses of the items of the folder you selected plus all contained folders' items, except of those that have the little blue checkbox to the left of their name unchecked. This allows you to fine-tune which folders' items actually get processed. E.g. you may uncheck the "Calendar" folder so that when you afterwards pick your Account folder as root folder for the extraction, it will effectively extract all emails' addresses but leave the calendar items' addresses unextracted..
All extracted email addresses – whether extracted from emails or calendar items – will be placed into a single .csv file named 'Email Addresses.csv' on a per-account basis. You'll find this file in a folder called 'Email Addresses' within the respective account folder of the Olminator output directory.
You can stop a lengthier extraction at any time by pressing the "Stop" button.
The progress of the email address extraction will be accordingly reported with a progress wheel on screen. You can't navigate to other sections in Olminator while Olminator is busy with the current content – my apologies.
Once the extraction is finished – either by having all items' email addresses extracted or by you having pressed the "Stop" button in between – the progress wheel will stay visible for a few seconds and then close automatically (you can also close it immediately by pressing the little chevron button in the Viewer's bottom action bar). Once it is closed, you can continue working with Olminator as before.
Please see the respective paragraphs in the documentation about configuration options, which can be found on the Configuring Olminator page. The most straightforward defaults have been chosen to guarantee a smooth extraction "out of the box". But if you're planning on importing the exported .csv file into Microsoft Excel afterwards, you may have to tweak the default settings of Olminator potentially.