Windows 10: How to fix file associations

Overview

in Windows, a file extension represents the file type (.pdf, .docx, .jpg, etc).  Each file extension / file type is associated with a default program that will open the file. A list of common file extensions and their file types as well as typical application associated with the file type is included at the bottom of this knowledge article. An example of a filename with the correct file extension is a Microsoft Word document named "I am a Word Document.docx". 

Sometimes the file extension will become renamed (the above example of a Word document with a .pdf extension for example making it "I am a Word Document.pdf").  To resolve this issue you can rename the file, changing the incorrect extension (pdf) to the correct one (docx).

In other cases the file extension is correct but the file type will be configured to open in the wrong application (such as a Word document opening in Adobe Acrobat).

It is possible to resolve both of these common issues in a few steps. 

For technical support please contact the Help Desk.

Details / Instructions

Situation 1: A file has the wrong file extension

1. Identify the file that will not open and determine what type of file it is (a picture, a Word file, an Excel file, a PDF file,).
2. Note the file extension - does it match the file type?

   If you cannot see the file extension in the filename, open File Explorer, click "View" at the top of File Explorer and put a check mark in the "File Name Extensions" box to enable file extensions being visible.

   

3. If the file type does not match the file extension, you can rename the filename, changing only the extension so it's correct.

   To rename a file, right-click the file and choose "rename" then change only the extension (the letters after the period) to the correct file extension. When the file has been renamed to the correct file extension hit "enter" on the keyboard to lock in the new filename. 

    Example: In the below image, "I am a Word Document" has a .pdf file extension. I can rename the filename from "I am a Word Document.pdf" to "I am a Word Document.docx" so it opens correctly in Microsoft Word. 

4. 

Situation 2: A file has the correct extension but opens in the wrong application. 

1. If the file extension is correct but the wrong application launches the file, right-click the file, choose "open with", click "choose another app", select the correct application in the list, put a check mark in the "Always use this app to open ... files" (this will vary depending on the file extension) and click OK.  

   

Common file extensions / file types: 

See Also