How to Change the App for “How Do You Want to Open This File?” in Windows 10

When Windows 10 shows “How do you want to open this file?”, it usually means that Windows does not have a usable default app associated with that file type. You can choose an app once, or make that app the permanent default for every file with the same extension.

Windows 10 itself reached the end of free support on October 14, 2025. The steps below still apply to PCs that continue to run Windows 10, but Microsoft recommends moving to a supported version of Windows when possible. See Microsoft's Windows 10 end-of-support information.

Why Windows 10 asks how you want to open a file

The prompt is not necessarily an error. It appears when Windows cannot confidently match the file to a default program. Common reasons include:

• No default app is assigned to that file extension.
• The program that used to open the file was uninstalled or its file association changed.
• The file type is unfamiliar and Windows does not know which installed app can handle it.

Change the app from File Explorer

The quickest method is to use Open with. This lets you test another installed app without changing every other file association first.

1. Open File Explorer and locate the file.
2. Right-click the file, point to Open with, and choose Choose another app.
3. Select the app you want. If it is not visible, choose More apps to expand the list.
4. If you want all files with this extension to use the selected program, check Always use this app to open ... files, then click OK. Leave that box unchecked if you only want to use the app this time.

Microsoft documents the same basic workflow in its File Explorer accessibility guide: choose Open with, select another app, and use the “Always use” option when you want a permanent association.

If the app you need is missing from the list

Choose More apps first. Windows may hide less frequently used programs below the initial suggestions. On Windows 10, the expanded chooser can also offer Look for another app on this PC, which lets you browse to an installed program's executable file.

Use that option only for software you already installed and trust. If you do not have a compatible program, search the Microsoft Store or the software publisher's official website for an app that supports the file format.

Do not simply rename the extension to make it look like another format. Microsoft notes that changing a filename extension does not convert the file's actual format.

Check the file extension before installing anything

If you are unsure what kind of file you have, identify its extension first. For example, .pdf, .jpg, .txt, and .docx each describe different file types.

1. In File Explorer, open the View tab and enable File name extensions if extensions are hidden.
2. Alternatively, right-click the file and select Properties.
3. On the General tab, check Type of file and the extension shown in parentheses.

Microsoft's guide to common Windows file name extensions also explains how extensions identify file types and how to find compatible apps for unknown formats.

Set a default app by file type in Windows 10 Settings

If the correct app is already installed but Windows keeps asking what to use, set the association directly in Settings.

1. Press Windows + I to open Settings.
2. Go to Apps > Default apps.
3. In Windows 10, select Choose default apps by file type.
4. Find the extension you want to change, such as .pdf or .txt, then click the current default app or the option to choose one.
5. Select your preferred installed app. The new association takes effect for files that use that extension.

Microsoft's current default-app documentation confirms that Windows lets you assign an app by file type or configure defaults for an application.

If the prompt still appears

Make sure the selected program still opens normally, then repeat the Open with process and choose the permanent “Always use” option. If the program no longer appears at all, reinstalling that application from its official source may restore its file-type registrations.

If only one unusual file triggers the message, the file may have the wrong extension or may be damaged. In that case, verify where the file came from before trying random programs. The safest fix is to identify the real format and use software that explicitly supports it.