Heres a few tips to ensure you successfully upload your .CSV to Mail Merge.
1. Your First Column heading must be "Email".
2.Ensure Excel is closed prior to upload.
3. There are a few different .CSV file types. You must save your file as the following:
CSV (Comma delimited) (*.csv).
4. Ensure your .CSV file does not contain any duplicate Email addresses - You can check this by highlighting your Email Column Click Conditional Formatting -> Highlight Cell Rules -> Duplicate Values.
5. Ensure all Emails are in the correct format, ie. has a .com / .org etc and the end.
6. Ensure there are no spaces after Column headings / or Email addresses.
7. Each column must have a heading.
8. Remove any columns not being used as a merge field.