“Macintosh HD” can’t be opened because the original item can’t be found.

Right I had this issue as well.

The way I fixed was as following:

1. Open a Finder window.
2. Open Finder Preferences.
3. In the 'Devices' section of the 'Sidebar' tab, click the option for your device name. In my case it's "Thomas's MacBook Pro".
4. In the Finder window, go to the Devices section in the sidebar. You should see your device name.
5. Click into this in the Finder - you should see your HD. Drag and drop this into the favourites or wherever you like and this should work as a new link. You can then remove the original link from the sidebar.

Hope this helps!

How exactly are you trying to open "Macintosh HD" in Finder?

What happens if you do the following? In Finder, use the Go menu to navigate to "Home". A window should open with its title being the name of your home directory. Command click on the title of that resulting Finder window. Can you select Macintosh HD there?

Alternatively: From the Finder Go menu, select "Computer". In the resulting Finder window what do you see?

Thanks for your response. I had to take it in to the techs at Apple Store to get this and other problems addressed, so, now, a few weeks later cannot remember exactly what they did to correct it, but all's fine now.

This.