Fixing Outlook Install Error "application with the same identity is already installed."
Go to Control Panel (Windows Start Menu > Control Panel) and search for Uninstall a Program. In here uninstall any instance of “sidekick” or “hubspot sales”.
Remove everything from from the folder at C:\Users\%YOURUSERNAME%\AppData\Roaming\Sidekick. If this folder is not visible you will need to display hidden folder. To do this select “organize” in the top right and then click “folder and search options”. In this new pop-up select “view” and on this page under “hidden files and folders” select “show hidden files and folders” and then click ok.
Go to Registry Editor by typing regedit in the start menu and clicking on regedit.
Click on the triangle next to HKEY_CURRENT_USER to expand it.