Optional argument must be Variant

Optional arguments can have any intrinsic data type, but it must be a type with a single default value. This error has the following cause and solution:

• You tried to specify Optional with a parameter that has no default value, for example, an array.

  Make sure any argument specified as Optional has a default value.

For additional information, select the item in question and press F1 (in Windows) or HELP (on the Macintosh).