What Stops the Shrinking of a Windows 7 Partition

I attempted to shrink the primary partition of an existing fresh Windows 7 setup so I could create several extended partitions.  I was able to shrink it but some immovable files were preventing further shrinking.  By stopping services, adding permissions, disabling hibernation, and reducing pagefile size, I was able to shrink the partition to the size I wanted.

I stopped the Cryptographic Services and Windows Search services and Full Control rights for my user account were applied to the file BootCLCK.etl.  This allowed the defrag program to move the previously locked files that we're preventing further shrinking.  This is useful for the next time I need to shrink the system/boot partition.