Hi Gunasekar,
I have a new twist on this same problem. I have Outlook pinned to my taskbar. When I click on the taskbar icon, I see the icon acknowledge that I clicked on it, but the Outlook app doesn't load. When I went to the app list through the start menu, and clicked on Outlook, it still didn't start.
Then I right clicked on the taskbar icon. It gave me some choices, like "send a new message: and "open calendar". I clicked on "open calendar" and then the Outlook Calendar opened. From there I could select "Mail" from the left-side menu, and Outlook immediately opened up to my email account. After processing my emails, I exited from Outlook. But when I clicked on the taskbar icon, the same old problem came up and Outlook wouldn't start from the taskbar icon.
Weird.
Terry