Microsoft added User Account Control to Windows in Windows Vista, and it’s still used on Windows 7 and 8 today. UAC restricts what programs can do without your permission.

Using an administrator account with UAC is a lot like using a limited user account. Programs don’t just get permission to do anything they want to your operating system — they have to ask first.

The Problem UAC Solves

Windows XP had a big problem. Most people used an administrator account to log into their PCs. This meant that every application had full administrator permissions to the entire PC. If you ran a malicious program, that program would have full read-write access to your entire operating system and could infect system files. If your web browser or another program you used was compromised, the attacker could use that program’s administrator permissions to infect the entire operating system.

People could choose to use limited user accounts instead, but many programs didn’t work when run as a limited user. Installing an application as a limited user meant using a clunky, hidden Run As feature.

How UAC Works

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In response, Microsoft introduced User Account Control in Windows Vista. When an administrator user logs into Windows, Windows actually starts the explorer.exe desktop process with limited user permissions. Applications you open are launched by explorer.exe and inherit its limited permissions. A program can choose to ask for those full administrator permissions — this will open the UAC prompt where you can allow or deny the request with a single click. The UAC prompt actually occurs on a restricted desktop programs can’t interfere with — that’s why it has a different, dark background.

This feature didn’t work that well in Windows Vista. Many programs weren’t designed to run with limited permissions and constantly request UAC permissions, while Windows itself was too noisy. It was improved in Windows 7 and 8 — after setting up your computer and installing your favorite programs, you shouldn’t see the UAC dialog very often on a modern version of Windows.

Why UAC is Popping Up

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Programs have to ask for administrator permission and display the UAC dialog when they need full administrator access. This often occurs when an application is installing itself — it needs to write to the Program Files folder and configure the system, so you’ll see a UAC pop-up when installing a program.

Some older programs — for example, many older games — were never designed to run without administrator access and must always be run with administrator permissions. They may ask for UAC permissions every time you launch them.

You’ll also have to agree to a UAC prompt when you do something that requires the elevated permissions. For example, let’s say you wanted to copy some files to the Program Files folder in Windows Explorer or File Explorer. You’d see a UAC prompt after attempting to move the files because Windows Explorer needs the elevated permissions to carry out your task. By default, the file manager runs with restricted permissions.

You should only accept UAC prompts if you’re expecting them. If you’re installing a program or making a change to system settings, go ahead and agree to the prompt. If you’re using your computer or browsing the web and a UAC prompt suddenly pops up, you shouldn’t agree to it unless you know what it’s doing. This can help prevent malware from infecting your computer.

UAC vs. Limited User Accounts

UAC makes administrator accounts function almost like limited user accounts. When you want to do something that requires administrator access as an administrator with UAC enabled, you’ll just need to click the Yes button in the UAC prompt to give yourself the permissions. Programs normally run without these permissions.

When you need to gain administrator privileges as a limited user account — for example, when installing software — you’ll see a similar dialog box. However, you’ll have to enter the password of a user account with administrator access to continue. Either way, you’ll see a prompt and will have to make a decision before you gain administrator access.

Limited user accounts are still different, of course. If someone doesn’t know an administrator account’s password, they won’t be able to gain administrator access. The process of typing a password can also slow down people and prevent them from immediately clicking Yes to grant the permissions.

UAC can be disabled, but we don’t recommend disabling it. The Windows software ecosystem and UAC itself have come a long way since it was introduced with Windows Vista. It’s an important security feature.

Profile Photo for Chris Hoffman Chris Hoffman
Chris Hoffman is Editor-in-Chief of How-To Geek. He's written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times and Reader's Digest, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read more than one billion times---and that's just here at How-To Geek.
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