I hear many problems with not being able to sync the partition table on GPT disks. Someone clams he has the solution to this. It's called GPT fdisk, which is a text-mode partitioning tool for Linux, FreeBSD, Mac OS X, and Windows that works on Globally Unique Identifier (GUID) Partition Table (GPT) disks, rather than on the more common (through 2009) Master Boot Record (MBR) partition tables. I personally have no experience with it but it sounds promising:
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