Automatically open downloaded MHT or MHTML files from the web in Internet Explorer mode
Setting this `REG_DWORD` value to `0` disables the automatic routing of MHT and MHTML files downloaded from the web to Internet Explorer mode.
since 0.9.8.11
Purpose
Show registry keys (1)
HKLM\Software\Policies\Microsoft\Edge\InternetExplorerIntegrationZoneIdentifierMhtFileAllowed
Setting this REG_DWORD value to 0 disables the automatic routing of MHT and MHTML files downloaded from the web to Internet Explorer mode. Microsoft Edge therefore does not automatically open these files with the IE mode engine.
The setting does not block the file types or disable Internet Explorer mode generally. It controls only whether the affected downloaded files are opened in IE mode automatically.
Notes
Possible side effects
MHT or MHTML files that depend on Internet Explorer-specific rendering or behavior are no longer opened automatically in the compatibility environment intended for such content.
Notes
The policy is supported on Windows in Microsoft Edge version 117 and later. Leaving the policy unset has the same effect on automatic opening as setting the value to 0.
Local MHT or MHTML files are not covered merely because they use one of these file formats. Their automatic handling in IE mode is controlled by the separate InternetExplorerIntegrationLocalMhtFileAllowed policy.
Microsoft documentation
Microsoft Learn: Allow local MHTML files to open automatically in Internet Explorer mode