What if you cannot see the file extension?

The file extension is the last few letters in the file name after the dot, but in Windows the file extension is now always visible. Windows prefers to hide the file extension so it is not visible.

Why has Microsoft done this? Well, there are advantages and disadvantes of hiding the file name.

Advantages of hiding the file extension include:

• Possibly it is an attempt to make the interface look simpler and less intimidating. This behaviour means that a document called "Report.doc" would appear simply as "Report" (with the ".doc" file extension hidden.) Windows will (hopefully) show the correct icon associated with the file to indicate that it is a document, and this avoids the less IT savvy from worrying about why the filename has ".doc" at the end of it.
• If you rename the file then you cannot accidentally change the file extension, so you won't be left wondering why your renamed file will not open.

Disadvantages of hiding the file extension include:

• It makes it easier for unscrupulous people to pass a file off as something else - in emails in particular you might come across something like "Invoice.doc.exe". With file extensions hidden this looks like "Invoice.doc" which looks innocent enough, and only the more technically savvy would appreciate that it is actually an executable file (and quite possibly a virus) and not a wordprocessed document. (This is a simle example of what is meant by a trojan horse.)
• Another disadvantage of this is that the file extension only implies the type of file, and sometimes Windows will prompt to open the file with the wrong application. With the file type hidden it makes it less intuitive to the IT savvy what the true file type is because they cannot easily see the file extension.

So there are advantages and disadvantages in hiding the file extension. In any event, if Windows has no idea what the file is (so if Windows does not recognise the file extension) then it will show it.

Fortunatly, it is very simple to tell Windows to always show the file extension:

1. Start Windows Explorer (note Windows Explorer, not Internet Explorer - possibly the simplest way to start this is to right click the "Start" button and select "explore").
2. On the menu along the top of the windows explorer window select "Tools" and from that menu "Folder Options...". If you don't see a menu along the top then press the ALT key, in Windows Vista and later the ALT key shows and hides the toolbar.
3. On the "Folder Options" dialog select the tab called "View".
4. You should now see the option "Hide extensions for known file types" (you shouldn't need to scroll to see this, although it will be near the bottom of the window). Simply uncheck this, so the box is empty without a tick in it.
5. Click [OK]

File extensions will now be visible for you.

You might also be interested in ...

You might find the following related FAQ articles of interest:

• What is a file extension?
• What is a file type?
• What is the difference between a file extension and a file type?
• Help determining the file extension