Mail Merge character limit
One problem you may come across is a field in Mail Merge is not picking up all the text entered into it (e.g. in the Excel data). Here is a work-around.
The system sets the data type by inspecting the first few record(s) in the data source.
A way around the problem therefore is to ensure that the first record in Excel (create a dummy one if necessary) contains more than the characters in the field that is being truncated.