Outlook will not let me archive old emails to a .pst file. The reason I want to do this is to free up space in my exchange online mailbox as it’s nearing it’s limit. I can tell it to do an archive, specify a date etc but it does nothing and all the old emails I told it archive are still there.
Outlook for some reason decides to archive based on modified date not sent or received date that you would expect. To remedy this you must first make sure that if you are using Outlook 2010 then you have applied the following hotfix first (not needed for 2013 or 2016) then add the following entry to the Registry.
Key for Outlook 2010:
Key for Outlook 2013:
Key for Outlook 2016:
You must restart Outlook after you add the ArchiveIgnoreLastModifiedTime registry.
Archiving should now work as expected.