Windows creates a profile for every user, which contains the changes made by the logged in user to the Windows configuration or application settings. These profiles are normally stored on the local computer, but domain admins can configure users so that their profiles are instead stored on a network share as a Roaming User Profile. This allows users to configure the appearance of Windows or make changes to a program’s configuration and have those same settings available on any other computer they log into on the same domain. Microsoft notes that this fix will only work if the Start Menu customizations that are stored locally and have not been deleted due to a group policy.
Source: https://www.bleepingcomputer.com/news/microsoft/custom-start-menus-in-roaming-profiles-reset-after-windows-10-upgrades/