If you export data from Conducttr, you'll find that dates and times are stored in Attributes as a very big number. Like this: 1453012064
To convert this number into a human-readable date and time in Excel or Tableau, you'll need this calculation:

Excel: <value>/86400+'1/1/1970'

Tableau: DATETIME(max(([DATE-TIME ATTRIBUTE]/86400))+date('1/1/1970'))

And then you'll need to format the cell as a Date & Time.
For example

Excel: BT2/86400+'1/1/1970' (BT2 is the cell where the data is stored)

Tableau:DATETIME(max(([Last Login]/86400))+date('1/1/1970'))