STEP 1: Copy the "Update Cache" folder to a new location. I copied folder "C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Update Cache" to "D:\JUNCTION" folder.

STEP 2: Delete the original "Update Cache" folder "C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Update Cache"

STEP 3: Create a directory junction for the original location to the new location
C:\>mklink /j "C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Update Cache" "D:\JUNCTION\Update Cache"
Junction created for C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Update Cache <<===>> D:\JUNCTION\Update Cache