Error message: Error opening workbook. Make sure Excel is installed

When trying to use Excel Application Scope, it throws an exception " Error opening workbook. Make sure Excel is installed". How to resolve?

Generally this error comes when there is an issue with the registry and UiPath is not able to communicate or reference the dlls of Excel.
Hence in order to resolve the issue, below steps can be performed - 
A) Removing Outdated References to Office from the System Registry

1. Close Excel and Project.
2. Go To Registry setting - HKEY_CLASSES_ROOT\Typelib\{000‌ 20813-0000-0000-C000‌ -000000000046} where is {00020813-0000-0000-C000-000000000046} Key for Excel
3. Click the + sign at the left of {00020813-0000-0000-C000-000000000046} to expand it. One or more subkeys will be seen:
    1.5 for Excel 2003.
    1.6 for Excel 2007.
    1.7 for Excel 2010.
    1.8 for Excel 2013.
    1.9 for Excel 2016.
4. Identify the one(s) that do not match the version(s) of Excel you actually have installed. If all of them do match installed Excel versions, omit steps 5 and 6.
5. Delete the key(s) that correspond to versions of Microsoft Excel that is not present. As a precaution, it is advised to take a back up. Right-click on {00020813-0000-0000-C000-000000000046}, select Export, and save the file where it should be found.
6. Right-click the 1.something key that does not belong, select Delete, and confirm the deletion. Repeat for each 1.something key that does not belong.
The {00020813-0000-0000-C000-000000000046} key can occur in more places. Usually they all have the same subkeys, but not always, so you need to examine each instance. Search for the Key to get to each of the others in turn. For each one, repeat steps 3 through 5 (click the + sign, export the key to a new file, and delete the orphaned 1.something entries).

B) Repair MS Office - You can refer to official link from office for the same. 
C) Reinstall MS Office - Once MS Office is reinstalled verify the registry structure as the one mentioned above