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What is an ASPX File?

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Question: What is an ASPX File?

Did you find an ASPX file on your computer and wonder what program should open it? Maybe someone emailed you an ASPX file but you're not sure how to use it. Perhaps you tried to open the ASPX file but Windows told you that it could not open it.

Before you can open an ASPX file (assuming it's even a file format that's intended to be viewed or edited), you'll need to determine what kind of file the .ASPX file extension refers to.

Answer: A file with the ASPX file extension is an ASP.NET Source file.

Other types of files may also use the ASPX file extension. If you know of any additional file formats that use the .ASPX extension, please let me know so I can update this information.

How To Open an ASPX File

The easiest way to open an ASPX file is to double-click on it and let your PC decide which default application should open the file. If no program opens the ASPX file then you probably don't have an application installed that can view and/or edit ASPX files.

Warning: Take great care when opening executable file formats received via email or downloaded from websites you're not familiar with. See my List of Executable File Extensions for a listing of file extensions to avoid and why.

Any web browser will open ASPX files - browsers like Firefox, Internet Explorer, etc. The actual code in the ASPX file is processed by the webserver and can be coded in any program that codes in ASP.NET (like Microsoft Visual Web Developer).

If you've downloaded an ASPX file and expected it to contain information (like a document or other saved data), it's likely that something is wrong with the website and instead of generating usable information, it provided this server-side file instead.

In that case, one trick is to simply rename the ASPX file to whatever you expect it to be. For example, if you expected a PDF version of a bill from your online bank account, but instead got an ASPX file, just rename the file as bill.pdf and then open the file. If you expected an image, try renaming the ASPX file image.jpg. You get the idea.

The issue here is that sometimes the server (the website you're getting the ASPX file from) doesn't properly name the generated file (the PDF, the image, the music file, etc.) and present it for downloading as it should. You're just manually taking that last step.

Sometimes the cause of this problem is browser or plug-in related, so you might have luck loading the page that's generating the ASPX file from another browser.

If you know anything else useful about ASPX files, please let me know so I can update this page.

Tip: Use Notepad or another text editor to open the ASPX file. Many files are text-only files meaning no matter the file extension, a text editor may be able to properly display the file's contents. This may or may not be the case with your particular ASPX file but it's worth a try.

If you find that an application on your PC does try to open the ASPX file but it's the wrong application or if you would rather have another installed program open ASPX files, see my How To Change the Default Program for a Specific File Extension guide for making that change in Windows.

How To Convert an ASPX File

There are two main ways to attempt to convert an ASPX file to another file type:

The first option involving opening the ASPX file in its native program is preferable because it's both easier and will probably result in a more accurate file conversion. Of course if you don't have a program that opens ASPX files, a third-party file conversion tool (the second option) could be very useful. Both of these options are only applicable if you're truly trying to work with ASPX files, not another format entirely that the ASPX file was supposed to generate (as discussed several paragraphs above).

Still Having Problems Opening or Using an ASPX File?

See Get More Help for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what kinds of problems you're having with opening or using the ASPX file and I'll see what I can do to help. ASPX files are particularly frustrating so don't feel bad asking for help.

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