This works for me:

Go to about:config in your URL bar. click the 'I'll be careful , i promise!' button and find the property browser.cache.disk_cache_ssl and change the value to false.

it still renames the files, but you will be able to open them.

I verify that the problem is caused by the update. I became aware of this problem when my first computer started acting like this and I came to this site for help.

I wanted to verify the cause and I opened another computer with FF 7.0.1. Tried to download pdf from OWA2010. It downloaded ok, with the right file extension name.pdf. After this, I updated the computer to the FF 8.0 and downloaded the same file again. Now the name has changed to attachment.ashx. No other other changes have taken place.

Any final fixes or better workarounds?

Using MacBook Pro running 10.5.8. Downloaded Firefox 8 on 11/9/11 and now Microsoft Outlook Web App 2010 downloads all email attachments as "attachment.ashx" instead of jpg, pdf, etc. Can open files if I change them to the proper extension, but no longer automatically open. Instead get a "can't open this file" message.  Attempted to fix in Firefox > Preferences > Applications by indicating the proper "Actions" for various "Content Types" but this had no effect. This is not a problem on Chrome or Safari browsers which continue to download email attachments properly.

The same here with OWA! I don't convince the first response. I hope will be a fix soon!

I just thought I would post a follow up to my original post in hopes that it might help point someone in the right direction.

I tried the solution posted above, but with no success. It did not make any difference to set browser.cache.disk_cache_ssl to false in the about:config.

I tried opening the attachments in various computers in my company's network, and there is something that I can not explain. When trying to open an attachment on one of my co-workers computers, the attachment will save as attachment.ashx and I have to rename the file extension so that the system will recognize it correctly. On my computer, with the same setup as the other (Win XP/Firefox8) attachments will download as attachment.ashx.EXT where EXT is the correct extension of the file. So if the file sent was file.xls, the attachment would download as attachment.ashx.xls. This effectively allows me to open the attachments without having to change the file extension (also, the above fix has not been applied on this computer).

I have many plugins/extensions installed in my firefox 8 that my co-worker does not, and think that this might be the reason that it works on my computer and not my co-workers. I think it may be one of the Microsoft related plugins, like the Microsoft Office 2003 plugin that is enabling my computer to at least detect the format and save it with the correct extension. Can anyone confirm this? (screenshot of installed plugins/extensions included)

Also, a sort of work-a-round that I've spread around the office temporarily is to right click the file, choose "Save As" and change the file name and extension of the file before you save it. This saves you from having to download attachment.ashx and then browsing to the file to change the extension before you can open it.

With file MIME type are those files send by the server?

You may have to check the registry for that .ashx file extension in HKEY_CLASSES _ROOT or search the MIME database key for that MIME type or file extension.

MIME Database : "HKEY_CLASSES_ROOT\MIME\Database\Content Type"

I updated into firefox 8 this morning and get same problem. All my attachment is .ashx. I can't do a lot of office works, as I need download and send many pdf files. Hope they can fix it soon.

So, I used Live HTTP Headers to check the mime type, and it is correct. It is also being sent with the correct file name... Please see the screenshot.

Also, I looked in the registry for .ashx file extension, and it does not exist in that location.

I also just realized that attachment.ashx is the file that is responsible for delivering the attachements to the user, thus why everything is being saved as attachment.ashx.

See Bug 699901 - All OWA attachments are saved as "attachment.ashx", some Chrome users met the same issues in 2010 (Microsoft released a patch).

I'm told by our IT department that we are already at update rollup 4, so I don't think that is the fix. Any other ideas?

I do not think that the filename is correct.
On the image I see:
Content-Disposition:attachment; filename*="CNF%20#1.xls"
This looks to me that the content-dispositon header is not complying with RFC5987. So the best way to solve this problem is to fix the program who sends these broken headers.

Find version 7 on the web and install over the top of 8. Problem solved!

What from I can see, there's no mention of this issue on the Firefox 8 Release Notes webpage: http://www.mozilla.org/en-US/firefox/8.0/releasenotes/

Does that mean this is not a bug with Firefox 8, but a bug with Microsoft instead?

We are deploying Firefox 8 to both staff / public users in our environment; all the PDF / Word / Excel / PowerPoint attachments are now turned into "Attachments.ashx"; this is really frustrating for us and our users; I do hope Mozilla can get onto it pretty soon.

BTW, Firefox 8.0.1 Build 1 is here; but it won't fix the issue; hopefully the next build will! ftp://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/8.0.1-candidates/build1/

At the end of the day, (assuming this is a bug with Firefox) we don't need the fastest / best looking browser in the world for corporate users, we just need one that's secure and works properly.

Hello Everyone,

   So I have the long awaited answer to this problem, but can not post it here because it's somewhat technical and in order to represent the problem it is necessary to use some characters that do not encode properly into this post, so I am providing a link to my solution:

http://www.nw-webdesign.com/MozillaHelp894442.php

Cheers :-)

Thanks titanicfanatic, I guess most users just have to sit and wait for Microsoft to release the patch!

If no one else gets to this before next week (busy and travelling for work atm), I'll look at seeing if I can write a Greasemonkey script that will fix it. Can't guarantee it's possible, but in theory, it should be doable.

Note: It's not a proper fix, but it should definitely allow people to get by till Microsoft get OWA back to working* again.

• - This is loosely termed, as with all large pieces of software.

There is a workaround by changing the user agent in Firefox 8 for Firefox 7. For that, use the add-on User Agent Switcher (but the spoofing is global) or another add-on called UAControl allowing to control the UA on a per-site basis. Try it.

I guess Microsoft should release a patch.

This did not work for me. I went back and found 7.0 loaded it and all was good. The minute I rolled out the 8.0 my attachments in OWA went right back to issue with ashx formatting. We use OWA 2010 and I have not issues with attachments in Chrome, or Safari. Just the 8.0 FF rollout.

Can you guys post a User-Agent string that works? Thanks.

I think that using a greasemonkey script is a fantastic idea.

I think maybe the way to go about accomplishing this is to modify the attachment link in OWA to point to a user defined script that will retrieve the raw data from OWA and then send that with the proper Content-Disposition. Not sure if this will work since the attchment would be requested from a different computer where you are not logged in.

Any other thoughts about this one?