Followup - Sorry, but I see that this topic already exists in a previous thread "MC19 ShellExtension breaks Win+X menu in Windows 8.1". Enabling Shell Extensions in MC19 fixed the problem.
I recently upgraded to Windows 8.1 after having successfully run Windows 8 and MC19 for several months. After the upgrade, I noticed that the subject menu would no longer work when accessed in my normal way via a right click in the lower left charm location (also accessed via Win button + x). Anyhow, to cut to the chase, I discovered that someone had already determined that it's caused by one or more desktop applications that install [Win 8 incompatible] shell extensions into the Windows right-click context menu. I used (as recommended by dannyboy75) Nirsoft's ShellExView and selectively disabled by "Company" until I narrowed it down to being JRiver's context menu shell extension (JRShellExt.dll v19.0.58.0). Just an FYI for anyone using Win 8.1 and that charm. Hope it helps someone pulling out their hair like I was.
Clarification - this problem affected all right click context menus, not just the charm I mention
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Topic: Win 8.1 Power User Task Menu (aka Lower Left Charm) (Read 3052 times)