Do you mean that tags applied on one computer don't appear on other computers, even if all have the same set of defined tags? Maybe the IMAP server doesn't support keywords:

http://kb.mozillazine.org/Tags#IMAP

Thank you for the fast reply.

The tags are customized tags and according to my colleague they are the same on all computers including the new one. The tags applied on one computer appears on all other computers except for the new one. If tags are created on the new computer they don't show up on the others as well.

I created a custom tag on one computer and applied it to a message in an account that supports keywords. On another computer, I defined a custom tag with the same name and color. When viewing the same account on the second computer, the tagged message displayed the correct tag and color, without my having to apply the tag manually. So, I can't explain your result. Note that the tags must be defined identically, manually, on all computers - tag definitions don't automatically sync. Tagged messages only sync the tag status if the tag definitions are the same and the server supports keywords.

Hi Sfhowes, thank you for the link (http://kb.mozillazine.org/Tags#IMAP). But, how can I login to the IMAP account? Could you tell me the steps?

Look for sites that explain how to query IMAP servers using telnet. Click the W10 Start button and type telnet to start the telnet client.

Thank you for the reply, please note that I don't have a technical background so this is a little to technical for me. Would it be possible for you to let me know the steps I should take?

I don't think you have to investigate the server, as it obviously supports keywords, as your experience with the other computers indicates. But what is different about the one computer that doesn't sync the tags? Does it not sync even the built-in tags 1-5?

We have 7 tags in total, and they all sync on the other computers. See screenshot for the different tags. The one computer that doesn't sync the tags is recently purchased, I had to install Thunderbird and all other programs on it before I was able to use it. So Thunderbird was installed recently. Do you know what I have to do?

The only thing I can think of is that the new computer has the account set up as POP in TB, which would mean there is no syncing of mail or tags.

Allright, and how do I set it up in the right way?

First, confirm that it is POP by looking at the Server Type at the top of Server Settings. If it's POP, copy the existing messages to Local Folders, then remove the account with Account Actions in Account Settings, and add it as IMAP.

http://kb.mozillazine.org/Convert_a_POP_account_to_a_IMAP_account

Can you see if it is POP? (see screenshot)

It's definitely IMAP (Servertype), so I don't know why the tags work differently than the other computers.

Hi, Do you know what else I can do to make them sync?