
Hi @Andy ,
Only Internet Explorer supports "Open with Explorer". The alternative suggestion is to use the OneDrive sync client. You can also use Add a network location from Windows Explorer and path appropriately to the site.
Quote from Microsoft:
Open with Explorer (in the classic SharePoint experience) and View in File Explorer (in the modern experience) are only available in Internet Explorer 11. These two options aren't available in other browsers such as Chrome and Microsoft Edge, and this situation won't change, because the underlying technology doesn't work in newer browsers.
Whether you're using Chrome, Microsoft Edge, Internet Explorer, or another browser, Sync is a faster and more reliable method for putting SharePoint files into folders you can see in File Explorer.
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