- C:\Program Files\Microsoft SQL Server\MSSQL\FTDATA\SQLServer\Config\noise.dat
- C:\Program Files\Microsoft SQL Server\MSSQL\FTDATA\SQLServer\Config\noise.eng
I stopped all the SQL Server services and the Indexing Service, but the files were still locked. After a little Googling, I found Unlocker, a very handy tool. This told me that the Microsoft Search service had the lock. I used Unlocker to remove the locks, made my edits, and restared all the services (including Microsoft Search for good measure).