Software & Apps File Types What Is an EX_ File? Decompressing EX_ files into EXE executable files by Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated on May 27, 2020 File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More Tweet Share Email A file with the EX_ file extension is a compressed EXE file. This format stores an EXE file with a smaller size to save storage space. You might also find the EX_ format within compressed installation files that you download from the internet. Windows can't execute an EX_ file. For example, you can't accidentally open an EX_ file to run the program until the file extension is renamed to EXE. Take great care when opening executable files. These files can be extremely dangerous to your system, personal data, and overall security. Never open an executable file sent to you over email or that you don't know explicitly what it does. How to Open an EX_ File You'll first need to convert the EX_ file to an EXE file before you can run the file. You can do that with the expand command from the Windows Command Prompt. How to Open Command Prompt in All Versions of Windows However, for this command to work, you have to make sure Command Prompt is working in the correct folder. After opening Command Prompt, use the dir command to change the directory to the one that has the EX_ file. Then, enter this command, substituting file.ex_ with the name of the EX_ file you want to expand (the second file.exe is the name you want to give the expanded file): expand file.ex_ file.exe The new EXE file will be created as named. No changes will be made to the original EX_ file. Another option for entering the expand command is to open Command Prompt and type expand followed by a space. Then, drag the EX_ file to the Command Prompt and drop it. This trick automatically fills the location and name of the EX_ file. Still Can't Open the File? If your file won't open at this point, make sure you're really dealing with an EX_ file. Some file extensions look really similar, and if you confuse another file for one that ends in EX_, and try to open it like you read above, it probably won't work at all. Some examples of similar file extensions include EX4, EXO, EXP (Symbols Export), and EX (Euphoria Source Code). If you have any of those files, you'll probably need a different program on your computer in order to open/edit/convert it.