You are not able to mass Update Accounts/Customers with the Country Information using Update option in Data Workbench.
Reproducing the Issue
1) Login to the HTML5 client
2) Go to Data Workbench workcenter
3) Select the tab Import
4) Select the object Account and Download CSV File
5) Fill the fields Internal ID, Country in the template
6) Select the radio button Update Data
7) Select Next and Browse for the file and Upload import
After Import you find the Country Information has not been updated.
In order to update Country Information, it is mandate to maintain the fields Country, Postal Code, State as per the country.
Please make sure to update these fields correctly in the template as per UI workflow.
For example if the country is India, then the postal code is of 6 digits. If country is US then postal code is of 5 digits etc.
1) Go to Data workbench workcenter
2) Select Export
3) Select the object Accounts
4) Filter required Account and Export
In order to update Country, maintain correct data in below mentioned fields in exporting template:
CountryCode, CountryCodeText ,CityName,StreetPostalCode
After updating the template with required information,
1) Go to data workbench
2) Select update
3) Select object Account
4) Import the template
KBA , LOD-CRM-ACC , Account , How To