Make sure the 2 UTF-8 encoding setting in Data Loader are checked.
Read all CSVs with encoding
Write all CSVs with encoding
Perform Export.and save the file on local file folder
3 Open Excel and import the file, on the MS Excel Import Wizard step 3, choose the File Origin Unicode (UTF-8).
Once the CSV is exported and displays symbols when opening in Excel. You may try these steps.
Right click on the csv file and click "Open With"
Choose Notepad
On Notepad click File then Save As
Set the file name - (Filename here).csv
Select UTF-8 on Encoding and click Save
Open the new CSV file on Excel.
Please TRY to use jitterBit data loader just as an alternative and if it still errors out then it confirms that there is something wrong with the file or the mapping file.
use the same data to create via UI, so it confirms whether the data in the file/mapping file is correct or NOT.
If the data load using JitterBit loader works then it is not a bug with salesforce.
Best Answer
As a starting point, have a look at the Data Loader Guide (pdf) and Data Loader Video.
Values separated by columns that you wish to map to a Salesforce objects field.
One way to use the dataloader is to create a field mapping from the columns in your CSV to the fields of a Salesforce object.
Have a look at Chapter 3: Using Data Loader in the PDF. In particular Inserting, Updating, or Deleting Data Using Data Loader on pg 12.