Seaquel
SQL Server error code

SQL Server error 9986

SQL Server raises error 9986 at severity 16, which marks a problem with the query or data that you can correct.

A search property list cache cannot be generated during full-text indexing. Attempting to query the registered search properties caused an internal error as indicated by the HRESULT error code, ((HRESULT = '0x%08x').
Msg9986
Severity16
Group9000–9999

Source: Database Engine events and errors