Is the problem when you are loading them from websites, or when you are loading them from disk (either because you're authoring a page or you downloaded it)?

Firefox does not pay much attention to the file extension (e.g., .aspx, .jsp, .php) and instead makes a decision on how to display the page based on the content-type indicated by the server. It would be strange to have this problem on a lot of different servers, since ASP.Net is a mature technology by now. Are there particular sites that cause this problem for you? A volunteer could take a look if you post a URL or two.

For files you download/save, you should change the ASPX extension to one that better identifies the file type, such as .html for web pages.

ASPX file extension is an ASP.NET Source file it can be open by any browser.

Tell me from where you got the ASPX file,

If you've downloaded it from a website and its is said to contain information (document or other data), it can be a problem with the website i.e it named the file extension wrong, change the .aspx to the PDF or Doc as required.

Regarding PDF file opening, Firefox can open PDF file by default. It will only download it only if you choose downloads for the extension.

You can change what Firefox should do for any file from

Firefox menu > Options > Applications tab> Choose any application

In your case PDF (Portable document Format), check what is the action. Change it to Preview in firefox to get it previewed or any other.

You can also search for the Content type.

When I download from websites. Certain files come with an .aspx although the button says "download pdf". As I said, IE opens them just fine. The particular site is the local clerk of courts office. Trying to download files and, as previously stated, the button says pdf but the file when downloaded has an .aspx. When I click on the file I get a new page but it is blank.

How would I change the aspx to pdf? As far as going to the menu/applications, I don't see an aspx in the list? Sorry, but I'm pretty rank in this department. Maybe it is the website and not Firefox, although as stated, IE opens them fine.

If you set Firefox to let you choose where to save the files, you can rename them as part of that process by changing the file name before you click Save.

If you set Firefox to always use your download folder, you would need to rename them in the folder. You can quickly access the folder using the download panel: the folder icon on the right side of a download opens the folder.

To make sure Windows shows you the extensions (otherwise they are quite difficult to edit!), see this article from Microsoft: http://windows.microsoft.com/en-us/wi.../show-hide-file-name-extensions.

Your download setting (always use 1 folder or choose folder every time) is described in this article: Startup, home page, tabs, and download settings.

Any luck?

By the way, it's very easy for a site's programmers to fix this problem and give you a good file name every time, but there isn't a convenient way for you to do that for yourself.

Notes for the developers:

• set the filename parameter of the content-disposition header to suggest a filename to a user agent

• to support browsers that won't read past a space in the filename parameter, replace spaces in the path with an underscore character so they read all the way to the file extension

A brief note about Internet Explorer: it actually looks at the beginning of the file to see what kind of content it contains and makes decisions based on that. So if the site's content-type header says, for example, "this is plain text" but inspection of the top of the file shows all the hallmarks of being an Excel workbook, you will get completely different results in IE and Firefox. This is a crutch that that web developers have relied on for years if they only test in IE. Sigh.

Okay, so what I did was open the download folder, right click the file, click properties and changed the program to open the files to IE. Works, but it seems to be the long way around. If IE can open the files I don't know why Firefox cannot. But then, I am not a huge techie in this department. Just want to be able to get information seamlessly. Thanks for all your help!

Hmmm, if they are PDFs, would it make more sense to change the program that opens them to Adobe Reader (or Acrobat, if you have it)? That's generally more full-featured than a browser plugin.

Either way, you won't have to rename files, so that will be faster for you.

When they open they are pdf's, but when the file downloads it has the .aspx extension. The download button on the website says "download pdf" but downloads with .aspx. I would use Adobe if it can open .aspx. I will experiment. Again, I'm pretty rank at this so many of these things don't make any sense to me.

Do these files work if you manually change the file extension to .pdf, either when saving the file or in Windows Explorer for already downloaded files?

It is possible that Firefox may not be getting the file name correct in some cases e.g. when the file is send as content-disposition.

I have this problem with aspx files as well and have been searching for months for a solution. In my case, it has nothing to do with PDFs being served up by aspx though. It's an autologon script used by Shoprunner on Newegg. If I clear cookies and cache and go to newegg and find an item that's shoprunner eligible, no problem - in fine print it has signup/login. If I login, then close firefox, from now on when I go back to newegg and it autologs me into shoprunner I get a popup "You have chosen to open: Login.aspx What should Firefox do with this file?" Oh, and it's a 0 byte file. I had read one suggestion that you set it to open with firefox. Well if you do that and check off do automatically, you just get an endless loop because it keeps serving up that file.

I've run safe mode with no addons, I've uninstalled/reinstalled Java and Firefox. I had actually given up and switched to Chrome but then recently I had reason to set my wife up on my PC with a separate Windows login. Well guess what, there's no problem with Firefox on her signon. I copied her firefox profile over to my login and it didn't help so I'm thinking it has to be something in my portion of the registry when I'm logged in, but I've searched and searched for differences and can't find anything aspx related.

Here's the Inspect for when the popup comes up if it helps: Request URL: https://secure.newegg.com/application/ShopRunner/Login.aspx?srtoken=bc5a8bcd4b964a62beeae46b6850e3686e0aede4 Request Method: GET Status Code: HTTP/1.1 200 OK

Request Headers: User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.0) Gecko/20100101 Firefox/25.0 Referer: http://www.newegg.com/Product/Product.aspx?Item=N82E16814202046 Host: secure.newegg.com Connection: keep-alive Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Response Headers: x-server-id: 154 Server: NEWEGG, NEG-Server Date: Thu, 21 Nov 2013 12:28:15 GMT Content-Length: 0 Cache-Control: private

Oh, and I just switched to my wife's login to turn on the inspector and the above looks the same for her, but no popup. Two other things. On my signon, the autologin is successful even if I click cancel to the aspx popup. Also, on her signon, right after the auto signon to shoprunner, this message shows in the console that I don't see.

[07:35:20.219] The character encoding of the plain text document was not declared. The document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the file needs to be declared in the transfer protocol or file needs to use a byte order mark as an encoding signature. @ https://secure.newegg.com/application/ShopRunner/Login.aspx?srtoken=1709911506578b05e25d775401457c8e19dad137

Hi fraenhawk, how did you copy over your wife's profile to your Firefox profile folder -- as a second Firefox profile? I'm not clear on how you tested starting up in her profile in your Windows account.

In your many experiments, did you ever rename or delete the mimeTypes.rdf file? It stores the associations for various content types and sometimes becomes corrupted.

Open your current Firefox settings (AKA Firefox profile) folder using

Help > Troubleshooting Information > "Show Folder" button

Leaving that window open, switch back to Firefox and Exit

Pause while Firefox finishes its cleanup, then rename mimeTypes.rdf to something like mimeTypes.old

Restart Firefox. Any improvement?

Has ShopRunner offered any tech support for this issue?

I initially tried creating a second, new profile. No difference. I then went into my appdata\Local\Mozilla\Firefox\Profiles and appdata\Roaming\Mozilla\Firefox folders, removed all profiles from there, went to her appdata (since she was a separate windows login) and copied her Profiles (Local and Roaming) and profile.ini into the appropriate directories on my appdata. When I restarted Firefox, I could tell I was running her profile successfully because her home page was now the same as on her login, and the cookies copied over so it auto-logged her into Facebook.

No, renaming mimetypes.rdf didn't help. Her profile works fine when logged into her windows login. No profile works when logged into my windows login, that's why I think it's an OS/registry setting in HKEY _CURRENT_USER not something in the Mozilla directories. I just have no idea what would control aspx file - especially since this is only affecting Firefox, not Chrome or IE 10 or 11.

aspx files suck. When you try to save a file that is an image file has been sent to you in as an attachment, it saves the file in a corrupt text form. You can't save the file let alone print the image. Its a pain in the ass. Save the fuckin shit as a jpg or gif or not at all for not everyone is using the save file formats as you maybe using. No matter how many times I try to resave a picture file into a jpg or gif or even an old format of tif it wont let you save it as a jpg or print the image and it may say jpg but because the file was sent via iphone or something else in the aspx format it won't save as jpg format and the aspx file will override it and only save or download as a aspx format. What crap!!

I hate these damn files

If Firefox offers to save the file with the wrong file extension then you need to supply the correct extension yourself or rename the file afterward.

Was experiencing the same and when you mentioned the ties to PDF, whala, it fixed it for me. Went to options and changed my selection for PDF.

Very, very helpful I am sure. I navigated to the site in question, clicked on the document to down load it, went to the green arrow at the right signed of the Firefox screen, clicked on it and tried to save it. When I right click I get a screen full of gibberish. When I simply click on the downloaded file, I get a message telling me that no file type is associated with that file name. That, in turn, took me to a site offering to let me download various files, which wanted to download the Ask toolbar to my computer. So, after I tried to follow these directions, I exited Firefox, loaded IE, and opened the document in question with IE. If someone figures out how to get dummies like me to understand what to do, please post.

Hi calcloud, was the problem with a link on this page, or another link? Could you post the link to the site and point out where it is on the page (not a direct link to the download, for security reasons). Thanks.