Indexing vanished on a single partition

[Guest Tom B in Oz]

Using Win10 a total lack of 'search' ability on my E: drive led me to rebuild indexing without a careful look. Rebuilding did not achieve anything.Only later did I realise that despite my E: drive being included (ticked) in my selected locations (on the right) that it was missing in the list (on the left). There was nothing I could do to have E: included on the left. See Pic below.The other weird thing is, as a test, I tried unticking some on the right to watch the effect on the left. Generally the result was as expected, however, when I unticked both E: and F: neither correctly appeare

 

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