There are duplicate company names in the "core_company" table.

The "Hash" field value in the "core_company" list view is the same.

- Check on the "Hash" field value of the duplicate company records.

All

The "core_company" table [sys_db_object] record, the 'hash' field does not exist in the "Database Indexes" related list.

Note: The highlighted Index is missing.

To be able to add the 'hash' index, please see the steps below: 

1. Navigate to the System Definition > Tables & Columns
2. Look for the 'Company [core_company]' from the list of 'Table Names' and select it.
3. Once the table is selected, Scroll down to the 'Index creator' section.
4. Select 'Hash' from the "Available' bucket and move it to the 'Selected'
5. Select the 'Unique Index' checkbox.
6. Click 'Create Index'.