Seaquel
SQL Server error code

SQL Server error 2512

SQL Server raises error 2512 at severity 16, which marks a problem with the query or data that you can correct.

Table error: Object ID %d, index ID %d, partition ID %I64d, alloc unit ID %I64d (type %.*ls). Duplicate keys on page %S_PGID slot %d and page %S_PGID slot %d.
Msg2512
NameDBCC_DUPLICATE_KEYS
Severity16
Group2000–2999

What it means

The two specified slots have identical keys, including any uniqueifiers.

Source: Database Engine events and errors