What you need before you start installing

Before you open any installer, gather three things: the program name or download link, your computer's password (you will need it to give permission), and about 10 to 15 minutes of uninterrupted time. Most installations fail because something interrupts the process halfway through — a system update, a sleep mode, or another program demanding attention.

Check that your computer has enough space. On Windows, right-click your C: drive and select Properties to see how much free space you have. On Mac, click the Apple menu, select About This Mac, then Storage. You need at least 2 to 3 gigabytes free for most programs, though some need more. If you are under 1 gigabyte, delete old files or uninstall programs you no longer use before you proceed.

Close all other programs before you start. This sounds extreme, but it prevents conflicts and stops your computer from getting distracted. Save any open documents first, then close your web browser, email, messaging apps, and anything else running in the background.

Key Takeaways

  • Download the installer from the official website of the program you want, not from random download sites, because fake installers can damage your computer.
  • On Windows, double-click the .exe file and follow the on-screen prompts, accepting the default folder unless you have a specific reason to change it.
  • On Mac, drag the program icon into your Applications folder, or double-click a .pkg file and follow the prompts the same way you would on Windows.
  • After installation finishes, restart your computer so the program can set itself up completely and work without problems.
  • If the installer gets stuck or fails, restart your computer and try again — most installation problems fix themselves after a restart.

Installing on Windows: the step-by-step process

Go to the official website of the program you want to install. Do not use a general download site like Softonic or FileHippo — those sites bundle extra software you do not want. For example, if you want Adobe Reader, go to adobe.com, not a third-party site. Look for a button that says Download, Get, or Install.

A file will appear in your Downloads folder. The filename will end in .exe (for example, GoogleChrome.exe or VLC.exe). Double-click this file. Windows will ask "Do you want to allow this app to make changes to your device?" Click Yes. This is normal and necessary — the installer needs permission to put files on your computer.

A window will open showing the installation wizard. Read each screen. Most of the time you can just click Next or Continue on every screen. Do not change the folder where the program installs unless you have a specific reason — the default folder is the right place. Watch out for checkboxes that say "Install toolbar" or "Set as homepage" — uncheck these if you do not want them, because they change your browser settings.

When you reach the final screen, click Install or Finish. The program will copy files to your computer. This can take anywhere from 30 seconds to several minutes depending on the program size. Do not turn off your computer or close the window while this happens.

When the installation finishes, restart your computer. This is the single most important step that people skip. Restarting lets Windows complete the setup and makes sure the program works correctly. After the restart, you will find the program in your Start menu or on your desktop.

Installing on Mac: the step-by-step process

Go to the official website of the program you want. Click Download or Get. A file will appear in your Downloads folder. The filename will end in either .dmg or .pkg.

If the file ends in .dmg, double-click it. A window will open showing a folder icon and an Applications folder. Drag the program icon into the Applications folder. This copies the program to the place where Mac stores all your programs. You can then close the window and eject the .dmg file by dragging it to the Trash.

If the file ends in .pkg, double-click it. An installer window will open. Click Continue, then read and agree to the terms if you are asked. Enter your Mac password when prompted — this is the password you use to log into your computer. Click Install. The program will copy files to your computer. When it finishes, click Close.

After installation, restart your Mac. Go to Applications in Finder, find your new program, and double-click it to open it for the first time. Mac may ask if you want to open it — click Open. This is normal for programs you have never run before.

What to do if the installation gets stuck or fails

If the installer window freezes and does not move for more than five minutes, force-quit it. On Windows, press Ctrl+Alt+Delete, click Task Manager, find the installer in the list, click it, and click End Task. On Mac, press Command+Option+Escape, find the installer, click it, and click Force Quit.

Restart your computer completely. This clears temporary files and resets your system. Then download the installer again from the official website — do not use the old file — and try the installation a second time. Most installation problems fix themselves after a restart and a fresh download.

If the installer fails with an error message, write down the exact error code or message. Search for that error code plus the program name on Google. You will usually find a support page or forum post explaining what went wrong and how to fix it. Common causes are not enough disk space, an older version of Windows or Mac that the program does not support, or a conflicting program already installed.

If you are still stuck after a restart and a second attempt, uninstall the program completely and try again. On Windows, go to Settings, click Apps, find the program, and click Uninstall. On Mac, open Applications in Finder, drag the program to the Trash, and empty the Trash. Then download and install fresh.

Uninstalling a program you no longer want

On Windows, go to Settings by pressing the Windows key and typing Settings. Click Apps, then Apps & Features. Scroll down and find the program you want to remove. Click it, then click Uninstall. A window will ask if you are sure — click Yes. The program will remove itself. Restart your computer when finished.

On Mac, open Finder and go to Applications. Find the program you want to remove. Drag it to the Trash, or right-click it and select Move to Trash. Empty the Trash by right-clicking the Trash icon in your dock and selecting Empty Trash. You do not need to restart.

Some programs leave behind small files even after you uninstall them. This is normal and takes up almost no space. You do not need to hunt for and delete these files — they will not cause problems.

Staying safe while installing

Only download from the official website of the program. If you search for a program name and see a download button on the first result, check the web address. It should match the program's real website. For example, Firefox's real website is mozilla.org, not some other site with Firefox in the name.

Be suspicious of download sites that show many ads or ask you to click through multiple pages before the download starts. These sites often bundle unwanted software with the program you actually want. If a site feels sketchy, leave and go to the official website instead.

Never download a program from an email attachment unless you know exactly who sent it and why. Malware often travels as fake installers in emails.

After you install a program, your antivirus software will scan it automatically. If your antivirus flags the program as dangerous, search for the program name plus "virus" or "malware" on Google. If multiple sources say it is safe, your antivirus may have made a mistake. If sources say it is dangerous, delete the installer and do not install it.

Frequently Asked Questions

Do I need to restart my computer after every installation?

Yes. Restarting completes the setup process and prevents problems later. Some programs will work without a restart, but restarting guarantees everything is set up correctly. It takes five minutes and saves you hours of troubleshooting.

What does it mean when an installer says "administrator permission required"?

It means the program needs permission to make changes to your system files. This is normal for most programs. Click Yes or enter your password when asked. If you do not have administrator access on your computer, you will not be able to install programs — ask the person who manages your computer to install it for you.

Can I install a program on an external hard drive or USB stick?

Most programs are designed to install on your main hard drive and will not work correctly from an external drive. Some portable programs can run from a USB stick, but these are the exception. Check the program's website to see if a portable version exists before you try this.

Why does my antivirus software block the installer?

Antivirus software sometimes flags legitimate installers as suspicious because they make changes to your system. If you downloaded from the official website and you trust the program, you can usually tell your antivirus to allow it. Look for a button that says "Allow" or "Add Exception" in the antivirus warning.

What should I do if I accidentally installed something I do not want?

Uninstall it immediately using the steps in the "Uninstalling a program you no longer want" section. If the program installed a toolbar or changed your browser homepage, you may need to change those settings back manually. Go to your browser settings and restore your homepage and search engine to what you want.