The basic way to open a file
To open a file, find it on your computer, then double-click it. Your computer will look at the file type — the letters after the dot in the filename — and open it with whatever program you have set up to handle that type. A file named budget.xlsx will open in a spreadsheet program. A file named photo.jpg will open in an image viewer. A file named letter.docx will open in a word processor.
If nothing happens when you double-click, or if the file opens in the wrong program, you can right-click the file instead. A menu will appear with options including "Open with" — this lets you pick a different program to use just this once, or set a new default program for all files of that type.
Files live in folders on your computer. On Windows, you find them through File Explorer. On Mac, you use Finder. Both work the same way: click through folders until you see the file you want, then double-click it.
Key Takeaways
- Double-clicking a file opens it with the program your computer has assigned to that file type.
- If a file opens in the wrong program, right-click it and choose "Open with" to pick a different one.
- You can set a new default program for a file type by right-clicking, choosing "Open with", then selecting "Always use this app".
- If you cannot find a file, use the search function in File Explorer (Windows) or Spotlight (Mac) to locate it by name.
- Some files need a program you do not have installed — you may need to download the right program first.
Finding files you have saved
When you save a file in a program, you choose where to put it. Most programs default to a folder called Documents, Downloads, or Desktop. If you remember which folder you saved to, open File Explorer or Finder and navigate there.
If you do not remember where you saved it, use the search function. On Windows, press Ctrl+F in File Explorer and type the filename. On Mac, press Command+Space to open Spotlight, then type the filename. Both will search your entire computer and show you every file with that name.
You can also search by file type. If you remember saving a photo but not its name, search for *.jpg (the asterisk means "any filename"). This works in both Windows and Mac search.
Opening files from inside a program
You do not have to find a file first. You can open a program, then open a file from inside it. In most programs, click File at the top left, then click Open. A window will appear showing your folders. Navigate to the file you want and double-click it.
This method is useful if you are not sure which program should open the file, or if you want to open multiple files in the same program. It also shows you only files that the program can actually open — if you are in a word processor and you open the file browser, you will see only documents, not photos or videos.
When a file will not open
If you double-click a file and nothing happens, the most common reason is that you do not have the right program installed. A file named presentation.pptx needs presentation software. A file named video.mp4 needs a video player. If you see a message saying the program is not found, you will need to download and install the correct one.
Sometimes a file opens but looks broken — text is garbled, images do not display, or the layout is wrong. This usually means the file was saved in a format that the program does not fully support. Try right-clicking the file, choosing "Open with", and picking a different program. You can also try opening it in a web browser, which handles many file types.
If a file is very old or in an uncommon format, you may need specialized software. For example, a file with a .psd extension is a Photoshop file and needs Photoshop or a compatible editor to open properly.
File types and what opens them
Your computer matches file types to programs based on the file extension — the letters after the final dot. Here are the most common ones and what usually opens them:
| File Type | Extension | Usually Opens With |
|---|---|---|
| Word document | .docx | Microsoft Word, Google Docs, LibreOffice |
| Spreadsheet | .xlsx | Microsoft Excel, Google Sheets, LibreOffice |
| Presentation | .pptx | Microsoft PowerPoint, Google Slides, LibreOffice |
| Adobe Reader, web browser, Preview (Mac) | ||
| Photo | .jpg, .png, .gif | Photos app, web browser, image editor |
| Video | .mp4, .mov, .avi | VLC, Windows Media Player, QuickTime (Mac) |
| Audio | .mp3, .wav, .flac | Windows Media Player, iTunes, VLC |
| Compressed folder | .zip | Built-in (right-click and extract) |
If you have multiple programs that can open a file type, you can choose which one is the default. Right-click the file, select "Open with", then choose the program you want. Look for an option that says "Always use this app" or "Set as default" to make it permanent.
Opening files from email or the web
When you download a file from the internet or receive one as an email attachment, it usually goes to your Downloads folder. You can open it from there the same way you would any other file — find it and double-click it.
Some web browsers let you open a file directly without saving it first. When you click a link to a file, the browser may open it in a viewer instead of downloading it. You can usually still download it by right-clicking the link and choosing "Save link as" or "Download linked file".
Be cautious with files from unknown sources. If you receive an unexpected file as an email attachment, especially one with an extension like .exe or .bat, do not open it unless you trust the sender. These file types can contain harmful software.
Frequently Asked Questions
What does it mean when a file says "file type not supported"?
The program you are trying to use cannot open that file type. You need a different program. Search online for the file extension (for example, ".webp file viewer") to find programs that can open it. Many file types have free options available.
Can I change the file extension to open a file in a different program?
No. The extension tells your computer what the file actually is, but changing the name does not change what is inside. A photo file renamed from photo.jpg to photo.txt is still a photo — it just will not open correctly in a text editor. Change the extension back to open it properly.
Why do some files have two dots in the name?
The file type is determined by the extension after the last dot. A file named document.backup.docx is a Word document. A file named archive.tar.gz is a compressed archive. Only the final extension matters for determining which program opens it.
What is the difference between opening and downloading a file?
Downloading saves a file to your computer so you can open it later. Opening displays the file right away. When you download a file from the web, it goes to your Downloads folder. When you open a file, your computer runs the program that handles that file type and displays its contents.
How do I open a file if I do not know what program to use?
Right-click the file and choose "Open with". Your computer will show you all the programs that might work. If none of them seem right, try opening it in a web browser — many file types display in browsers. You can also search online for the file extension to find programs that support it.