Windows 10, like Windows 8 before it, is integrated with Microsoft’s online services. Microsoft would prefer you sign into Windows with your Microsoft account, although you can still create a local account. Certain features are only available if you sign in with a Microsoft account, however.

What Is a Microsoft Account?

There’s a good chance you already have a Microsoft account, even if you’ve never used Windows 8 or Windows 10 before. A “Microsoft account” is the new name for Microsoft’s online account system, which was previously known as Windows Live ID, Microsoft Passport, and .NET Passport.

If you’ve ever registered for Hotmail, Outlook.com, Windows Live, Xbox Live, Office 365, or any other Microsoft online service, you already have a Microsoft account.

While most Microsoft accounts will probably be associated with an @outlook.com, @hotmail.com, or @live.com email address, you can create a Microsoft account linked to any email address. For example, you could have a Microsoft account linked to your @gmail.com or @yahoo.com email address.

The Windows Features That Need a Microsoft Account

Windows 8 and 10 both push you towards creating a Microsoft account when you set up your PC. There’s a good reason for this—some features are only available with a Microsoft account. You’ll miss out on them if you avoid using a Microsoft account. But you can still choose to sign in with a Windows 7-style local account.

In Windows 8, many of the included “Store apps” (unofficially known as “Metro apps”) required a Microsoft account to function. You couldn’t even use the Mail app with your Gmail account without providing a Microsoft account first.

In Windows 10, Microsoft has lifted this arbitrary limitation and you can use included apps like Mail, Maps, and Music without a Microsoft account. However, all the online features that allow you to sync your data and purchases between your devices will require a Microsoft account. Try to access such features in some apps and you’ll be prompted to add a Microsoft account.

The Store app included with Windows 8 required a Microsoft account to download apps, but you can now download free apps like Netflix in Windows 10’s Store app without a Microsoft account.

You’ll still need a Microsoft account to purchase paid apps, however. Purchased apps are tied to a Microsoft account so you can re-download them on all your PCs.

OneDrive, available on Windows 8.1 and 10, requires a Microsoft account as well. You won’t be able to synchronize files with the OneDrive service built into File Explorer without a Microsoft account.

Microsoft’s cloud file storage tool works a lot like Dropbox or Google Drive. The files you store here are also available on the OneDrive website, OneDrive smartphone apps, and OneDrive clients for macOS and Windows 7.

Other syncing features require a Microsoft account, too. Windows can synchronize your desktop settings, including your background and color choices, between your PCs. Other apps like Microsoft Edge synchronize your favorites and other browser settings between your PCs.

On Windows 10, you can see and manage which types of settings sync at Settings > Accounts > Sync Your Settings. On Windows 8, they’re available at PC Settings > Sync Your Settings.

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Initially, the Cortana personal assistant included with Windows 10 required a Microsoft account to function. In the Anniversary Update, Microsoft updated Cortana so it will function even if you’re signed in with a local user account. However, many Cortana features rely on personalization and will only function if you use a Microsoft account. To make Cortana as powerful as possible, you have to leave the local user account behind.

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Windows has “family” features that provide parental controls, allowing you to restrict and monitor what children can access. These require a Microsoft account. The Microsoft account also gives you access to an online dashboard where you can manage child account permissions and monitor usage information.

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The features in Windows 10’s Xbox app require a Microsoft account. Sadly, you can’t record your PC gameplay with Game DVR, stream games from your Xbox One to your PC, or stream live TV from your Xbox One with a local account.

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If you took advantage of the free Windows 10 upgrade offer in the first year—or one of the free Windows 10 upgrade paths Microsoft is still offering—a Microsoft account can help you. As of the Anniversary Update, you can sign into Windows 10 with your Microsoft account and it will automatically save information about your digital license in your Microsoft account.

If you ever have trouble reactivating Windows after reinstalling it—perhaps you replaced some hardware—you can use the new activation wizard to associate your PC’s hardware with a license saved to your Microsoft account. You’ll see a “Windows is activated with a digital license linked to your Microsoft account” message at Home > Update & Security > Activation if your digital license is linked to a Microsoft account.

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Device encryption, a feature introduced with Windows 8.1 that’s still present on Windows 10, also requires you sign in with a Microsoft account. When you sign in with a Microsoft account on a new PC that supports device encryption, it will automatically encrypt your hard drive to protect your data. Anyone who rips out your PC’s hard drive won’t be able to access your files without the key.

Windows only activates the encryption if you sign in with a Microsoft account. That’s because Windows 10 will upload a recovery key to your Microsoft account online, ensuring average PC users who forget their passwords can still access their files.

Windows won’t encrypt your hard drive if you sign in with a local user account. People would forget their passwords and complain to Microsoft that they can’t access their files. If you want to encrypt files with a local user account, you’ll need the BitLocker encryption feature that’s only available on Professional editions of Windows.

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Microsoft is continuing to add new features that depend on a Microsoft account to Windows 10. Windows 10’s November Update added a “Find My Device” feature for portable PCs, allowing you to track a stolen or lost PC if you set this up ahead of time.

This feature requires a Microsoft account. Microsoft provides a “Your devices” website where you can track the location of your lost PC. Just click the “Find my device” link next to the device you want to track.

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Joining the Windows Insider Program to get the latest testing builds of Windows 10 before they’re stable also requires a Microsoft account. You’ll need to link a Microsoft account and opt into the Windows Insider program before you can download the latest unstable builds of Windows 10.

How to Switch Between a Microsoft Account and Local User Account

Windows guides you towards signing in with a Microsoft account, whether you’re creating a new account when setting up a PC for the first time or you’re adding a secondary account later.

For example, to add an account on Windows 10, you have to head to Settings > Accounts > Family & Other People > Add Someone Else to This PC. The first screen will ask you for the email address or phone number associated with the other person’s Microsoft account.

To bypass this screen, you have to click “I don’t have this person’s sign-in information”. You’ll be taken to a screen that prompts you to create a new Microsoft account.

To skip creating a Microsoft account, you have to click “Add a user without a Microsoft account”. You’ll then be able to create a local account.

Whatever type of user account you create, you can head to Settings > Accounts > Your Info and use the “Sign in with a local account instead” or “Sign in with a Microsoft account instead” option to switch between types of user accounts.

On Windows 8, you’d have to use the PC Settings > Users > Add a User option and click “Sign in without a Microsoft account”. By default, Windows 8 also encourages you to use Microsoft accounts.