Efficiently change a single file extension in Windows

You could try cmdHere (Power Toys) and then using move filename.jpg filename.jpeg. Or you could Press F2 for rename (If it works with disabled extensions!).

But you should enable extensions anyway. As i would think it is a security risk to have them disabled. An attacker could send you an file like "Really Important Filename".exe With an standard icon included in the .exe making it look like an Word, Excel or Text Document. You might then click it unaware of the .exe file format. THIS is an EVIL feature of Windows.

I would recommend using the command-prompt as well, but with either of two different methods.

1. • Open a command-prompt (I like to set the shortcut in Start->Accessories to have a hotkey like Ctrl+Alt+P to make it quick and easy, though Start->Run->cmd.exe works just as well)
   • Type ren "
   • Drag-and-drop the file in question to the command-prompt window
   • type " " (there’s a space between the quotes)
   • Drag-and-drop the file again
   • Press Backspace and change the extension as desired
   • type "
   • Press Enter
   • Close command-prompt

It looks like a lot, but it is actually not and takes about three or so seconds to do (editing the extension is the most time consuming part).

2. (supposed to be 2, markdown limitation)
   • Install a program like Kai Li’us CmdOpen (I prefer this to the older Microsoft PowerToys one because it supports elevated prompts and has the source available)
   • Open a command-prompt in the folder where the file in question is contained (right-click on the window where the file is located and press ‘A’ or select Open command prompt
   • Press Tab a few times until the desired filename is displayed
   • Press Space
   • Press Tab again until the filename is displayed again
   • Edit extension
   • Press Enter

This method is also pretty quick, but if there are a lot of files in the folder, using method one is faster.