In this basic article, aimed primarily at the less experienced, we see how to show the file extensions on a Windows PC and how to change them, which is important to know how to use the computer correctly. Knowing what type of extension a file has is very important both to understand well with which program to open it, and for safety reasons, to immediately identify possible dangers or viruses.
A file extension identifies the type of file and is indicated by Windows in the file name, represented by three letters preceded by a dot.
For example, a PDF file has a name like foo.pdf, a file created with Word has the extension .doc or .docx, with a name such as foo.docx, while an executable file has the extension .exe instead.
However , file types can also be recognized by the icon, which however is not always visible and can often be misleading.
READ ALSO: How to change a file extension in Windows 10
On Windows PCs, by default, file extensions are hidden so that a user cannot change them when trying to rename them.
In fact, if you rename a file from pippo.pdf to pippo2 thus deleting the extension, that file becomes of an unknown type and Windows does not know with which program to open it.
Conversely, since the character of., if the extensions were hidden and the problem was ignored, it could happen that an executable malware, whose full name was document.docx.exe (therefore with the extension .exe), appears with the name document.docx and you might think that it is a normal file to open with Word which, if clicked, would run the virus.
Furthermore, knowing what extension a file has is useful for understanding which program to open it with, because if a cbz, flac, iso, rar, mkv or other common but lesser known file format happens, it becomes easy to search the internet for the right program.
On each PC I therefore recommend seeing the file extension, which is easy, that Windows, whatever version it is (Windows 7, Windows 8, Windows 10) hides in a folder settings option.
From the Control Panel then open Appearance and Personalization and then Folder Options .
In the window that opens, switch to the Display tab and remove the cross on the " hide extensions for known file types " option.
Press on Apply, then on OK, close and note that in each folder the file names have the three letters after the dot that identify their type and format.
In Windows 10 you can activate the display of extensions also by opening any folder and, from the top menu, pressing on View and then on Options or, directly and quickly, pressing on Show and Hide and activating file extensions.
In Windows 7, instead open any folder, press Alt on the keyboard to bring up the menu bar at the top, click on Tools -> Folder Options .
Once the extensions are activated, when changing the name of a file, be careful not to change even the three letters after the dot, which must remain the same if you do not want to change the type of file.
It therefore becomes obvious that to change the extension of a file just rename it by changing only the three letters after the dot.
For example, a .txt file created with the notepad can become a .bat file if it contains a programming code that you want to run.
One trick that can come in handy regarding file extensions is to make a document or photo impossible to open or recognize.
In fact, if the photo claudio.jpg is given the name casa.ppp, Windows no longer knows that it is an image file and, by clicking on it, it will detect it as an unknown file impossible to open if a suitable program.
Obviously just change the name again and put jpg to reopen it normally or you can tell Windows to open that file with the image viewer.
Renaming a file by changing the extension is not the same as converting it to another format.
In another article we have seen all the programs to convert files to different formats, which Windows alone cannot do.
In other guides of this blog we have seen:
- What to do if a file does not open because it has an unknown extension or if the wrong program is used.
- Find the program to open an unknown file that is not recognized by Windows
READ ALSO: Change file associations with the default programs in Windows
