A supplier sent me a .zip with an .exe installer inside and Outlook says "Outlook blocked access to the following potentially unsafe attachments". I trust the sender. How do I get the file?

Outlook blocks file types that are often used to spread malware, like .exe, .bat and .js. The easiest and safest way is to ask the sender to put the file in a password protected archive with another extension or share it through a cloud link like OneDrive or Google Drive.

You can unblock a type yourself with a registry value. Under HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Security add a string value called Level1Remove and enter the extension, for example .exe. Restart Outlook.

I would only do that for a short time and only when you know the sender is real. On a work PC your admin may block it through policy, so check with them first. After you save the file, scan it with your security software.

Asked them to share a OneDrive link instead. Much cleaner. Thanks.