App Store not functioning after High Sierra

Hello,

Before upgrade: OS X Yosemite (10.10.5), 21.5 inch Mid 2010.

Some background: [if unnecessary please skip to the bold sentence below.]

I was trying to download the full High Sierra (4GB) in order to make a bootable drive for a clean install.

That didn't work out as I was only able to download the 22 mb version of the installer. a bummer.

Anyway, I was having a problem because the High Sierra did appear in my updates tab in App Store and I could click "UPDATE" but it would immediately show me an unclickable "Installed" button after clicking it and in 3 seconds turn back to a clickable "UPDATE".

When checking About this mac I would see that the macOS isn't Hight Sierra although App Store shows update was installed.😕

Here are some screenshots for clarification: (This is what I could see even after clicking UPDATE/UPDATE ALL)

But if you scroll down you see: (an installed update for every time I clicked any of the UPDATE buttons)

So long story short I gave up and manually downloaded High Sierra (22 mb version) from App Store by searching for it, and installing it. Although I would still like to make a clean install by downloading the full installer.

Now the problem is the App Store isn't functioning after the upgrade.

• Every time I click the updates tab on App Store it freezes.
• Every time I hover over "store" near the "edit" and "App Store" it freezes.
• Moreover, trying to download High Sierra just turns the button to an unclickable "DOWNLOAD" and does nothing.

I tried deleting "com.apple.appstore" folders from "/private/var/folders" and from "~Library\Caches".

What can I do?