Assume that you create a primary key on a column which includes large decimal values or numeric values in Microsoft SQL Server 2012, 2014 or 2016. Then, you create a full-text index by using this column as the unique key index. In this situation, if there are some rows that are failed to be indexed, the full-text key value will be record as a negative number or unicode characters. Therefore, you can't identify the rows which are failed to be indexed.
This issue is fixed in the following cumulative updates for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:
To work around this issue, add a unique bigint or int column to the table and specify full-text by using that column instead. Int and bigint correctly report their values to the full-text error log when a failed row or document is reported. The unique column used by full-text doesn't have to be the primary key of the table.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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