User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; cs; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5 (.NET CLR 3.5.30729) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.5) Gecko/20091130 Thunderbird/3.0 When I am trying to open text attachment (which is sucessfuly shown in preview windows), it fails, because text editors (notepad and PsPad tried) got link imap:\\mail_account@server143\fetch%3EUID%3E.INBOX%3E1480?part=1.2&type=text\plain&filename=PT7801.TXT instead of downloading file to temp and opened from them (which is doing for other attachments). Same behaviour seen with POP3 accounts. Reproducible: Always

How do you try to open them ? Do you have the the same issue in safe-mode (http://kb.mozillazine.org/Safe_mode) ?

(In reply to comment #1) Doubleclick on txt file in attachment bar placed in bottom of mail view window (same behavour if I opened mail in new Window). Thinderbird is asking: "This link needs to be obened with an application. Send to:" But it is not link at all. It is plain/txt file (PT1701.TXT in my case). I could forward some mail with it, if you will. Tried safe mode, no change.

Seeing the same effect (since rc2): Also it seems that TB tries to open the txt file as an imap URL instead of a Type Text file - asking me what type of app should be used for imap urls (win xp). note: save as is functionning correctly.

Just adding few things. - U have seen this on RC1 too. I haven't tried earlier versions. - On POP3 account, link is (for example): mailbox:\\\C|\Documents%20and%20Settings\user\Application%20Data\Thunderbird\Profiles\74c622br.default\Mail\Local%20Folders\Inbox?number=220177084&part=1.2&filename=PT7801.TXT&type=text\plain&filename=PT7801.TXT

I see the same behavior also double clicking on text attachments in the composition window.

Same behavior here, with both Windows 7 x86 and x64 (I tried with pop3 i can try imap in the evening), if I try to open a plain *.txt attachment i get the window that ask me wich program it should use to open the link... Got this since rc1, it worked well in beta 4 (didn't try earlier betas) To reproduce it just autosend to yourself an email with a txt attachment and double click it on the bottom message pane with attachments, even if the message is opened in a new tab. PS: Save as... is working as it should :)