Turn on Enhanced Protected Mode

Purpose

Show registry keys (2)

• HKLM\Software\Policies\Microsoft\Internet Explorer\Main\Isolation
• HKCU\Software\Policies\Microsoft\Internet Explorer\Main\Isolation

This policy controls Internet Explorer Enhanced Protected Mode. When enabled, it applies Enhanced Protected Mode to every security zone in which Protected Mode is already active. It does not independently enable Protected Mode for zones where that underlying protection is turned off.

Isolation is a string value (REG_SZ). PMEM selects Enhanced Protected Mode, while PMIL selects the original Protected Mode. When the choice is enforced through policy, users cannot override it in Internet Options.

Notes

Security

Enhanced Protected Mode places web content in a more restrictive execution environment. On Windows 8 and later, it further limits the file-system and registry locations that Internet Explorer can read. Its AppContainer isolation also restricts access from a compromised tab process to higher-privilege processes and to sensitive personal or organizational data.

On 64-bit systems, 64-bit tab processes can provide additional resistance to memory-safety exploits. Their use is also governed by the separate Isolation64Bit policy value, however, so setting Isolation must not be treated as equivalent to enforcing that separate 64-bit-process policy.

Possible side effects

Toolbars, browser extensions, Browser Helper Objects, and ActiveX controls can load only when they are compatible with Enhanced Protected Mode. Legacy web applications that depend on incompatible add-ons may therefore lose functionality or fail to work correctly.

If a site requests an incompatible ActiveX control, Internet Explorer can offer to run that site under regular Protected Mode. Whether this lower-isolation fallback is available depends on the separate DisableEPMCompat policy.

Notes

This is a legacy Internet Explorer policy available in both computer and user configuration. It does not restore the standalone Internet Explorer desktop application on Windows versions where that application has been disabled.

Microsoft documentation

Microsoft Learn: InternetExplorer Policy CSP – AllowEnhancedProtectedMode

Microsoft Learn: Internet Explorer settings – Enable Enhanced Protected Mode

See also

• Entry in the reference