Sounds like you have deleted emails and not compacted the folder to remove all the 'marked as deleted' but hidden emails. This means the file is still full of emails you thought you had deleted. As it seems you have not been compacting on a regular basis and just in case there is any corruption on that file, please do the following. * Move all good emails out of the Inbox into suitable folders for storage. * Right click on 'Inbox' folder and select 'Compact'. * Right click on 'Junk' folder and select 'Empty Junk'. * Right click on 'Junk' folder and select 'Compact'. If you enable the 'Folder Pane Columns' (located under 'Menu icon' > 'Options' > 'Layout' ) then you will be able to see the 'Size' of folder. It may help to remind you compact folders on a regular basis. see images as guide.