field for mapping not available to select when merging csv

[kharpbrown]

Hello, 

I'm trying to merge a CSV but the field that I need to map to is not available to select. I can't select the field I need as the merge field. It is not one of the options in the "choose a field" drop down.

[ScottWorld]

Please don't post duplicate posts. Your other post on this topic is here: https://community.airtable.com/t5/other-questions/merge-problem-field-not-available/m-p/170336/