Office 365 SharePoint Online error "Your client does not support opening this list with Windows Explorer"

If you get this error there could probably be somehting wrong with the WebClient service. So the first step would be to verify the WebClient Client service on your computer.

1. Click the "Start" Button in the "Start Search" bar, type: "services.msc" (without quotes) and press Enter. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
2. Double click the service "WebClient".
3. Click on the "General" tab; make sure the "Startup Type" is "Automatic" or "Manual". Then please click the "Start" button under "Service Status" to start the service. If the service has been started already, please stop the service, restart the computer and restart the service.

Please check the “Open with Explorer” issue again.  If the issue persists, please continue to perform the following steps. After each step, please click “Open with Explorer” to check the results again.

4. Add your team site to the “Trusted sites” location of browser.

5. Clear the browser cache.
 

6. Uncheck the “Enable Protected Mode” of your browser.
7. Use 32-bit IE browser to open your team site, do not use 64-bit IE browser.