Why is Dreamweaver CS5 so slow to sync files when target is local system folder?

Dreamweaver can create a cache file in which to store information about all the links in your local folder. This cache file is updated invisibly as you add, change or delete links on your local site. This can have as effect the extreme slow-down of file copy operations.

To disable, use the Edit > Preference menu to bring up the Preferences Dialog. In the General Category, set "Update Links When Moving Files" to Never. Never does not automatically update all links to and from the copied documents.

See also Why has Dreamweaver become slow/unresponsive?, where two solutions are listed (to do while DW is closed) :

1. Corrupt cache : Navigate to C:\Documents and Settings\[your username]\Application Data\Adobe\Dreamweaver [version]\Configuration and delete the SiteCache folder.
2. Corrupt synchronization files : Navigate to target directory, open the '_notes' folder and delete the file named 'dwsync.xml'. Search if you have such a file on your local computer.