[quote]outlook 2016 collapse defaults not working Every time I pick "All collapse" from drop list as default choice for inbox or for sent folder outlook not save this option. please help me.By alnuaimi[/quote] I am experiencing exactly the same thing. I have set the default for "All collapse" and it has worked in the past. Now, when I set it (per the instructions above) for a folder of processed/retained mail items, all the groups collapse at the time I set it. Then, I expand a group, leave the folder, and return to the folding expecting to see all the groups collapsed. Instead, the group I had opened is still open and the View settings have been changed to "As last viewed." Interestingly, this change in settings does not occur if I leave all folders collapsed, exit and return to the folder. It only changed if I have I expanded a folder(s), depart, and return. I have "Reset" folder settings to Default and applied the change to All collapse. No joy. I am using Office 2016 (from Office 365). Observations/solutions welcome.

What worked for me was going group by group and doing the steps:

1- Click on the group
2- Click on View
3- Click on View Settings
4- Group by -> All collapsed -> Ok -> Ok

I did it for each group independently and is working fine.

Regards,