HubSpot Sales for Outlook install error: 'an application with the same identity is already installed'

You may encounter the following error message when attempting to install the HubSpot Sales Outlook desktop add-in:

Unable to install this application because an application with the same identity is already installed. 

To resolve this error: 

1. Uninstall the Outlook desktop add-in.
2. Copy and paste %appdata%\Sidekick into the Start menu in Windows and press Enter.
3. Delete all the contents in this folder.
4. Navigate to the Registry Editor by typing regedit in the Start menu and pressing Enter.
5. Click the > icon next to HKEY_CURRENT_USER to expand the folder.
6. Expand Software > Microsoft > Office > Outlook > Add-Ins. 

7. Right-click the Sidekick folder and select Delete.

8. Collapse Add-Ins > Outlook > Office so you're back in the Microsoft folder.
9. Expand VSTA > Solutions.
10. Under Solutions, you'll see one or several folders. Click one to view a list of files in the right-hand pane of the window. 
11. Go through each folder under Solutions and find one in which the value in the Data column for the ProductName file is HubSpot Sales for Outlook. 
12. Delete the entire folder that contains the HubSpot Sales for Outlook ProductName file. 
13. Attempt to install the HubSpot Sales Outlook desktop add-in again.