Another discovered detail - While in a folder, after clicking the "move to next unread" button through each unread message till I reach the last unread, message, if I then click on an already read message in the same folder, rather than clicking the "move to next unread message" button, then, the last unread message is marked read. SO, it's only when I click to continue to the next unread message using the menu button that I leave behind a message still marked unread, even though I'd just displayed it. To reiterate, only the last unread message in any given folder exhibits this issue.

re :I configured mail to be marked read immediately upon display

When you are reading the second to last email, it should already be marked as read and the last email is still unread, so that when you click on 'Next unread' button the focus moves to the last email amd marks it as read immediately. The selected last email should be changed to read status when selected. Are you saying that it does not mark immediately as read when you have focus on the last email? That is before you click on 'Next unread' button to go to next in a different folder.

Does it do this if you use the arrow keys on your keyboard to move to next in the list; the last one?

What sort order are you using? eg: View > Sort by > Date - Descending - unthreaded

Please confirm you have this: Tools > Options > Advanced > Reading & display tab select: 'automatically mark messages as read' select: 'Immediately on display'

Replies are interspersed below:

re :I configured mail to be marked read immediately upon display

When you are reading the second to last email, it should already be marked as read and the last email is still unread, so that when you click on 'Next unread' button the focus moves to the last email and marks it as read immediately. The selected last email should be changed to read status when selected. Are you saying that it does not mark immediately as read when you have focus on the last email? That is before you click on 'Next unread' button to go to next in a different folder.

• That is correct. It does not mark a message as read until I click to go to the next unread message.

Does it do this if you use the arrow keys on your keyboard to move to next in the list; the last one?

• The down arrow key only moves the focus to the following folder, and does not land on or display a message in that folder

What sort order are you using? eg: View > Sort by > Date - Descending - unthreaded

• I'm using different sort orders depending on the folder, but generally, it's Sort by > Date - Ascending - and either threaded or unthreaded (some folders have no threaded conversations so there's no need to choose threaded)

Please confirm you have this: Tools > Options > Advanced > Reading & display tab select: 'automatically mark messages as read' select: 'Immediately on display'

• Those are the settings I have. I've tried changing them and setting to After Displaying for 1 second, and then restarting; then, changing back to Immediately on display, and restarting, but nothing changed

re: Does it do this if you use the arrow keys on your keyboard to move to next in the list; the last one?

The down arrow key only moves the focus to the following folder, and does not land on or display a message in that folder

If the focus is on the Folder in the Folder Pane , then the arrows will move up and down the Folder Pane list.

If the focus in on a selected email in the list of emails you can use the up and down arrows to move up and down the list. As you select an email, it is displayed in the Message Pane below and marked as read. I use this method alot as it is quicker than moving the mouse over any buttons.

I'm trying to work out if this is something related only to the 'Next unread button' or whether something else is conflicting. I presume if you click on the email it is marked as read.. So please tell me if the use of arrows to select emails, still causes the issue.

Test if the Sort Order effects the marking of the last unread email. Please select the following Sort Order and tell me if the 'Next unread' button works with a different Sort by order. View > Sort by > Date - Descending - unthreaded

Do you use the 'Quick Filter Bar' to 'Show only unread messages' - icon looks likea pair of sunglasses? If no. could you please test. Select the 'Show only unread messages' - then use the 'Move to the Next unread mesage' button. Does it still fail to mark the last email as read?

What version of Thunderbird are you using? What OS ? Confirm Pop or imap mail account?

Please test whether their are any addons causing a conflict: In Thunderbird 'Help > 'REstart with Addons disabled' then use the Next unread button method to see if it works ok. If it works ok then an addon is causing an issue.

I don't have access to the machine at the moment, but I will respond tomorrow morning when I'm at work

duplicate

I'm trying to work out if this is something related only to the 'Next unread button' or whether something else is conflicting. I presume if you click on the email it is marked as read.. So please tell me if the use of arrows to select emails, still causes the issue.

• use of the arrows to select emails has the same result - the mails are not marked as read till I move to the next message

Test if the Sort Order effects the marking of the last unread email. Please select the following Sort Order and tell me if the 'Next unread' button works with a different Sort by order. View > Sort by > Date - Descending - unthreaded

• changing to this sort order didn't fix the problem

Do you use the 'Quick Filter Bar' to 'Show only unread messages' - icon looks likea pair of sunglasses? If no. could you please test. Select the 'Show only unread messages' - then use the 'Move to the Next unread mesage' button. Does it still fail to mark the last email as read?

• no change in the behavior - only marks a message read after clicking the next unread button

What version of Thunderbird are you using? What OS ? Confirm Pop or imap mail account?

• Thunderbird 31.0

  Windows 8.1 Enterprise
  All my email accounts are configured as POP

Please test whether their are any addons causing a conflict: In Thunderbird 'Help > 'REstart with Addons disabled' then use the Next unread button method to see if it works ok. If it works ok then an addon is causing an issue.

• I did this and it fixed the problem. I started re-enabling various add-ons and it turns out the problem is being caused when I enable Cloudmark which is an anti-virus add-on.

Good to hear your issue is now resolved. Many thanks for your excellent feedback on locating which addon caused the issue; this may be of use to others.

After discovering this issue, I sent a message to Cloudmark. Today, they came out with Ver 1.8 (I was running Ver 1.7). Removing Ver 1.7 and installing Ver 1.8 resolved the problem - messages are now being marked read as soon as I move to them, including the last unread message.