[jdelStrother]

That's just a single regular apostrophe? At least on my machine, with Mac Excel 15.38, if I have a CSV containing:

1,foo,'=SUM(A1:A10),bar

and open it, then the single apostrophe is visible in the cell.

[elliottcarlson]

You should actually append it to the trigger; i.e.

1,foo,='SUM(A1:A10),bar