Maybe it's different problem, however I have fixed the issue myself, the apps that were missing were in c:\windows.old... path under Menu Start of <All Users> and not particular user and seems that...

I found the instruction on how to 'edit' the 'All Apps'

How to move or remove apps in All Apps in the Windows 10 start menu - gHacks Tech News



I've fixed that by copying the Menu Start from...

I think it's not the case as some of the installed (non-standard) apps were created there while others not. Like for example Flux, FlacSquisher or JDownloader.
26793

Hello, did you managed to fix that, I just created a thread but seems we are facing the same problem.

Missing applications in Start Menu after upgrading from 7 to 10 - Windows 10 Forums



For...

Hi All,

I've just upgraded yesterday from Windows 7 to Windows 10, operation went smoothly, after around an hour of additional configuration tasks I'm almost 'at home'. However what I noticed and...