How to solve error: "Read range : Not a legal OleAut date." in excel?

I was having the same issue and it was due to for some weird reason the “read range” activity couldn’t actually get the cell or it would get it in the wrong format instead of just the value of the cell.

What worked for me is putting the read range activity in a “Excel Application Scope” which effectively quickly opens excels, does what ever is in it’s scope and closes excel. After implementing that it was able to pick up on the values in excel.

Another option would be to try and print the value of the cell before you do anything to it to make sure you’re returning a correct value.