For a while now, I have had the issue that I could not open Excel sheets (files) by double-clicking them in the Windows Explorer, nor could I directly open Excel sheets sent to me in email from within Outlook. I got an error like this: “Cannot find the file path (or one of its components). Make sure the path and file name are correct and that all required libraries are available.”
Turned out this is a fairly common problem, with a documented solution.
For some reason, you need to go into Excel options and have it allow other programs to access Excel via DDE, as in the screenshot below: