Uninstall and reinstall programs for all users or enable UAC back.
I have reinstalled StartAllBack for all users, same issue. I'm not sure what you mean by enabling UAC back.
I have the same issue and have sent an email about it. I am missing a lot of default applications in my start menu like paint, 3d paint, etc. If I try searching for them I "working on it..." .If I go to all programs I do not see them listed there. Ive disabled SAB for now in order to find the apps I need.
By the way, if it's any help whatsoever, this only occurs on my Legion 7 16achg6 laptop, my desktop can access the menu just fine.