That version behaves as expected on my end. When I try to reproduce your problem, I get a prompt for what Thunderbird should do with the file. That prompt gives me the option to open the file using the program I choose or save the file. When I open a message that has a pdf attachment and double-click the attachment, it opens in Thunderbird's pdf (pre)view(er). This is in line with my preference which is set to "Preview in Thunderbird".

This is very strange. Following your reply I tried to change the configuration to 'Always Ask' but it still opens a new 'Write' window. Please note that it behaves as expected when reading emails, the problem only happens when writing a new email.

I have exactly the same problem. I'm running 91.2.1 (32-bit) and when I am composing an email and click on a pdf attachment in it to check it, it opens a new compose window rather than opening the pdf. Very annoying as I have to waste time finding the file again and opening it just to check it is the correct one.

I also can't open PDFs in emails that I am writing since the update, but I don't get the compose new email issue. Mine just provides the option to open with applications that aren't PDF readers, or to save the file.

Hi Guys,

I solved this problem for me. My Thunderbird was reading the .pdf as a html file In composition which I think is a bug.

Under Preferences and Under Files & Attachments - select Firefox HTML Document And either delete or change action to use adobe acrobat reader and it should solve the problem.

Thank you Brendan, it worked for me. Only difference is that I had to delete Chrome HTML Document instead. So I guess delete "Tour Main Browser" HTML Document for it to work.

Thanks both of you. That sorted it for me. It still identified the pdf as html, even after I deleted the html entry in Files & Attachments and restarted. However I just forced it to use Adobe Reader instead of the offered choices.