The following CSV file(s) have errors in them and can't be imported into the system: Multiple values found for a dropdown field that can only take one when importing a record with External ID that uses special character

To remove the Field mapping Error:

 

1. Navigate to Setup > Import/Export > Import CSV Records.
2. Set the Import Type to Items and Record Type to Inventory Item.
3. Click the Select button and upload the CSV file. . Click Next.
4. Data Handling = Add. Click Next.
5. On Advanced Options >

Custom Multi-Select Value Delimiter = put any special character that is not used on the string "SNG-EDUC|SKU-1004921210/08/2010|14:06:00"
eg.
| Pipe
/ Slash
: Colon
- Hypen
   Space 
 
6. Set Multi-Select Value Delimiter to NULL will give the error because NetSuite considers it as Space