Microsoft Outlook file is missing in Indexing options

Hi Brink,
Iam using windows 10 Home version. My emails in outlook 2016 is to be indexed.
My problem with indexing options is that Iam unable to modify and put the folder of Microsoft Outlook in to "Index these location" list. Earlier it was there as per below picture:

Earlier the indexing of mails was was working fine, Now this Microsoft Outlook file is missing in Indexing options.
When tried to add by going to modify button so that my outlook 2016 mails can indexed for search again, Iam unable to find this MS outlook ( as marked in the picture ) when i go by the modify button to access it.
I thought it got deleted, later went and checked the normal way by as per the target location of ms outlook i could find it.
Please advise how to solve this, as without MS outlook in the "Index these location" list we will not be able to index emails right?

Well, as no-one else has offered to help yet: firstly, it would help if you included a screen-shot of the options available when you try to modify the indexing. This is what mine looks like:

Note that the options under Outlook (2010 in my case) are for each email account. Note also that it takes ages for poor old Windows to respond to the 'modify' button.

screenshots: learn to use the snipping tool, as it produces cleaner, easier to read, results than a photo.

waiting to hear back, Martin