I tried this with two IMAP accounts. The first one retained the tag when I pressed A to move it to the IMAP Archives folder. The other account lost the tag. I think this is just what happens with tags in general: some IMAP servers don't support IMAP keywords. In that case, messages that are tagged on one computer are not tagged when viewed from another computer.

If you change the Archives folder location to Local Folders, are the tags retained?

Thank you for answering.

So I did the test as you requested, when I change the Archives folder location to Local Folders and the press A to archive a message with a tag it retains the tag.

What I find odd is that when I drag and drop the message with tag to the Archive folder on the server it does retain the tag. This tells me the server should support it.

The help document you linked has a link to an external page http://bobpeers.com/technical/telnet_imap.php but this page no longer exists. I found a good alternative here: https://busylog.net/telnet-imap-commands-note/

So I used openssl to log into the mailbox and see that the PERMANENTFLAGS is supported. See the response:

``` a SELECT INBOX

• FLAGS (\Answered \Flagged \Deleted \Seen \Draft NonJunk wzh $label1 $label3)
• OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft NonJunk wzh $label1 $label3 \*)] Flags permitted.
• 25 EXISTS
• 0 RECENT
• OK [UIDVALIDITY 1546353124] UIDs valid
• OK [UIDNEXT 146] Predicted next UID
• OK [HIGHESTMODSEQ 398] Highest

a OK [READ-WRITE] Select completed (0.002 + 0.000 + 0.001 secs). ```

The wzh is my own custom tag. I do not know what the $label1 and $label3 is.

Does this help?

Your tests do shed light on the issue, but to be sure that the server really does support tags, I would set a tag on one computer, then see if the tag is visible when the (IMAP) message is viewed on another computer. That would indicate the tag is not just stored on the computer on which it is applied.

Hello,

So I checked the emails on another computer and the tags are not showing up.

This raises the question, the mail server seems to indicate that it supports tags but it doesn't seem to work.

Since I have control over the mailserver, is there something I should check on the mailserver?

Thank you so much for assisting with this issue.

I'm afraid I don't know how to configure a server to work with tags (custom flags, keywords), although yours suggests that it should work. But a quick search shows there is information available for a variety of mail servers. I have one account that works properly with tags, but I couldn't say what server software is used or how it's set up.

Thank you for the insights. I am going to dig deeper into this and update this thread with my findings.

Hello,

Just to update you here. When I logged into the webmail, it is actually showing me the tags. However on the other computer they still didn't show up.

Then it hit me, Thunderbird is missing the tags. So when I added the tags to Thunderbird on the computer where they were not showing up, they started to show up on the messages.

Conclusion is that whatever tag I create I must create it on all other machines where I use Thunderbird as well.