MacOS Mail app drops "Dock unread count" and "New message notifications" preferences

I have the same issue.

I also went through with Apple support and replicated it in a separate admin account, and in safe mode.

Currently awaiting feedback from an escalation.

Will post updates on here.

I found that if I did not quit the app then I could retain the settings as desired.

I also found on occasion that I was required to firstly select "All Mailboxes" for both "Dock unread count" and "New message notifications", then select the desired Smart Mailbox. I don't remember exactly when/under what circumstances I was required to do this, and no not care to investigate this further but just incase someone wants to try this also.

BTW

The file which was being reset for me was:

~/Library/Containers/com.apple.mail/Data/Library/Preferences/com.apple.mail.plist

The following .plist entries were being reset upon opening Mail.app again after either quitting, or a system restart.

• [array] MailSections
  • [string] MailUserNotificationMailbox (this entry would simply be removed)
  • [number] MailUserNotificationScope (this entry would reset from "4" to "0")

Thanks for replying, Monsignor Paolo, and that additional info, it really helps! Next, use safe mode to start up your Mac as it does the following things:

• Verifies your startup disk and attempts to repair directory issues, if needed
• Loads only required kernel extensions
• Prevents Startup Items and Login Items from opening automatically
• Disables user-installed fonts
• Deletes font caches, kernel cache, and other system cache files

Log in to your user account and test the issue while in safe mode and then restart normally and test the issue again.

How to use safe mode on your Mac How to use safe mode on your Mac - Apple Support

If you see the same behavior in safe mode, please contact Apple directly to investigate this further: Get Support

Have a great day and thanks for using the Apple Support Communities!

Hi Monsignor Paolo,

Thank you for using the Apple Support Communities! If you create a test account, does the issue remain? Being able to see if the issue occurs in another user account will to identify if it is something that is affecting your entire system or just one particular user account. To do this, you'll want to set up a Test User account and then try to replicate the issue in that account.

1. Choose Apple menu > System Preferences, then click Users & Groups.

2. Click the lock icon, then enter an administrator name and password.

3. Click the add button (+) below the list of users.

4. Complete the fields shown for a Standard or Administrator account, then click Create Account (or OK).

5. Go back up to the Apple menu in the upper left of the computer and select "Log Out". At the login screen, choose the "Test User" just made.

6. Once inside the Test Account, try to replicate the issue to determine if it just occurs in one account or on the whole computer.

Thank you.

Have you installed and run any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac?