It's possible that antivirus programm on your machine may accessing it.

Also make sure that you have detached the database properly. Check for the same using sp_helpdb.

Jeff,

That's why you are champion !!! 🙂

But I think one can use Truncate_only with proper planning...

If your database is not configured for Replication or Logshipping you can use following command to shrink your databse log file to death:

backup log with truncate_only

dbcc shrinkfile...

You can also use SSIS for transferring Jobs and Logins from your primary server to secondary server.