Since started using the new Outlook on my new laptop, I found it’s a little bit annoying that the column width in the mail list pane did not stay. Every time after I set the comfortable width of each column so I can easily read and spot the email I am looking for, if I go to a different folder and come back, all the column width set back to default. This never happened in earlier versions, it might only apply to the latest versions 2016 and 365..
So how to fix that? There is a new “Automatic column sizing” option in Outlook. You can find that by right-clicking the heading in mail list pane and choose “View Settings”, then “Other Settings”. From there, you can uncheck “Automatic column sizing”, and do more customization in “Format Columns…”
I checked on my other PC using Outlook 2013, it has the same option but it keeps user setting intact instead of restoring to default every time.