You can not use GetHistData as Excel function in a cell as this function returns array.
In our sample excel workobook, we added a sub that will download OHLC using GetHistData and write it to a excel sheet.
You can use that sub as a reference or modify it to suit your requirement.
To get OHLC data you need to subscribe for Historical API.
Edit your existing subscription in developer console and subscribe Historical API (No need to create new separate subscription for Historical API, and our excel will not work with standalone Historical API subscription)
@howutrade the minor or major depends on usage of the APIs. My whole algo depends on reading prev day intra and his data and run regression on it,
Due to change in directoy it just stop in midway when the algo could not find the required csv in the folder it supposed to be.