Information
This policy setting controls whether MHT or MHTML files that are downloaded from the web are automatically opened in Internet Explorer mode. MHTML files are archives of HTML code and companion files such as images and audio.
The recommended state for this setting is: Disabled.
Internet Explorer is officially retired and unsupported. Opening files in an unsupported browser that does not have modern protections in place could lead to an attack that exploits a vulnerability in the legacy software.
Solution
To establish the recommended configuration via configuration profiles, set the following Settings Catalog path to Disabled :
Microsoft Edge\Automatically open downloaded MHT or MHTML files from the web in Internet Explorer mode
Impact:
MHT or MHTML files will not open in Internet Explorer mode.