Comment 27 for bug 988583

I'm also affected by this on Ubuntu/precise (Mint/maya). I have my internal laptop drive with dual boot HFS+/Mac OS X and ext4/GNU/Linux. The grub-mount hang never happens with that disk. It does happen when my external backup disk is attached. I thought maybe it had something to do with how the disks were partitioned. Here's my internal disk that works fine:

$ sudo parted /dev/sda
GNU Parted 2.3
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
Model: ATA ST9750420AS (scsi)
Disk /dev/sda: 750GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Number Start End Size File system Name Flags
 1 20.5kB 210MB 210MB fat32 EFI System Partition boot
 2 210MB 483GB 483GB hfs+ Untitled
 3 484GB 645GB 161GB ext4 Untitled
 4 645GB 666GB 21.5GB ext3 Apple_HFSX_Untitled_4
 5 666GB 750GB 83.8GB ext3 Apple_HFSX_Untitled_2

Here's the backup disk that triggers the problem:
$ sudo parted /dev/sdb
GNU Parted 2.3
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
Model: WD Ext HDD 1021 (scsi)
Disk /dev/sdb: 2000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number Start End Size File system Name Flags
 1 20.5kB 210MB 210MB fat32 EFI System Partition boot
 2 210MB 400GB 400GB hfsx BIGBACKUP
 3 400GB 2000GB 1600GB ext4