What does "won't open" look like? I mean that seriously as files of this type generally go wrong via and over helpful antivirus products locking the file when it is written to the TMP folder and the handle passed to the operating system to open.

Hence what it looks like, if it is just apparently nothing, I would start with the security software.

.docx attachment: "clicking Open does nothing". No response, zilch, nada. Saving attachment to e.g. Desktop (or anywhere outside of Thunderbird) will then Open normally. .doc: attachment Opens normally from Thunderbird .xlsx: attachment Opens normally from Thunderbird .pdf: attachment Opens normally from Thunderbird etc As shown in screenshot attached to first email, there is no reference to .docx in the 'Files & Attachments' Settings in Thunderbird and I can't see a way to add file types.

(PS: thanks for responding!)

Help/Troubleshooting Information, Profile Folder, Open Folder, close TB, delete or rename handlers.json, the file that stores helper apps for attachments. Restart TB and Open an attachment, and Browse.. (not select from the list) to the executable for the file, e.g. word.exe, and check the box to have this action remembered.

Thank you: this works perfectly for all attached file types that I've tried other than .docx. It allows me to open .docx (hurrah) but as 'Read Only' in Viewing Mode. While I can then click on the Viewing button and select 'Allow Editing' this is not something that I've seen before when opening attachments in previous iterations of Thunderbird/Windows. It happens even on .docx attachments that I've sent myself, and these certainly aren't set to Read Only... What am I missing? Thanks again for your help

Not a Word user, but it might be due to a setting mentioned in item 4 here.

Thank you: this works perfectly for all attached file types that I've tried other than .docx. It allows me to open .docx (hurrah) but as 'Read Only' in Viewing Mode. While I can then click on the Viewing button and select 'Allow Editing' this is not something that I've seen before when opening attachments in previous iterations of Thunderbird/Windows. It happens even on .docx attachments that I've sent myself, and these certainly aren't set to Read Only... What am I missing? Thanks again for your help

You are missing that the file is created on the fly and stored in the system temp folder and no changes are saved when you close it. Therefore the read only opening.

Despite appearances an attachment is not a "file" it is a stream of mime encoded text in the body of the email. When you chose to open or save the attachment, the stream is decoded and written as a file. For "open" this file is written to the temp folder and is deleted again once the helper application closes. Therefore there is basically no honest way to open the file than as read only as any changes made will be lost on closing.

Not a Word user, but it might be due to a setting mentioned in item 4 here.

Thanks for the tip, but that setting is already unticked (i.e. not set to open attachments Read Only). This issue only happens in Thunderbird: I've just checked and if I email the same attachments to my rarely used hotmail account they open normally in Word

I'll continue to try to find a solution!

Chris

chris571 said

Thank you: this works perfectly for all attached file types that I've tried other than .docx. It allows me to open .docx (hurrah) but as 'Read Only' in Viewing Mode. While I can then click on the Viewing button and select 'Allow Editing' this is not something that I've seen before when opening attachments in previous iterations of Thunderbird/Windows. It happens even on .docx attachments that I've sent myself, and these certainly aren't set to Read Only... What am I missing? Thanks again for your help

You are missing that the file is created on the fly and stored in the system temp folder and no changes are saved when you close it. Therefore the read only opening.

Despite appearances an attachment is not a "file" it is a stream of mime encoded text in the body of the email. When you chose to open or save the attachment, the stream is decoded and written as a file. For "open" this file is written to the temp folder and is deleted again once the helper application closes. Therefore there is basically no honest way to open the file than as read only as any changes made will be lost on closing.

Thanks Matt, but as I've just replied to sfhowes - having followed their tip about the handlers.json file which at least allowed me to open .docx within Thunderbird (if Read Only), and having looked into their tip about a setting in Word - this is only an issue in Thunderbird and not in Hotmail. So it seems to be a Thunderbird foible to me. Perhaps one day I'll find a full solution! Thanks again, Chris