By default, Windows Explorer shows file extensions only for files that don’t have an association with a program. That makes it awkward if you want to edit a file’s extension. To make all file extensions visible for editing in Windows XP, open Windows Explorer and choose Tools, Folder Options. In the Folder Options dialog box, click the View tab and clear the checkbox to the left of the Hide extensions for known file types option. Click OK to close the dialog box and return to Windows Explorer. You can now see and edit all extensions.
Personally, I think that option is too drastic. I don’t want to run the risk of accidentally changing a file name extension for a Word document or an executable file. But I do find it handy to show extensions for certain types of file, such as text files with the .txt extension. And it’s relatively easy to make those extensions visible. Here’s how:
- Choose Tools, Folder Options.
- Click the File Types tab and select the entry associated with the extension you want to make visible — in this example, choose the TXT extension, which is associated with the Text Document file type.

- Click the Advanced button to open the Edit File Type dialog box.
- Select the Always show extension checkbox.

- Click OK to close the Edit File Type dialog box and then click OK to close the Folder Options dialog box.
Now return to Windows Explorer and you’ll see that the .txt extension is visible (and editable) in every Explorer window.
