Gparted not working: "Invalid partition table on /dev/sda --wrong signature 0"

[m654321]

I have an LL3.4/Win7 dual-boot setup on a single 250GB SSD, for a Dell Latitude D630.
However, I needed a bigger drive for more data files and also a Windows recovery partition, the latter apparently needing a significant about of disk space.

So, I cloned the above set-up onto a 500GB SSD using the 'dd' command:

Code:

sudo dd if=/dev/sdd of=/dev/sdc

Then, I replaced the laptop's 250GB drive with the 500GB one, and was able to boot into either Win7 or LL3.4 on the larger drive, without any apparent problem. So far, so good 

Next, I tried to open gparted in order to resize some of the partitions on the new larger drive. However, gparted remained stuck indefinitely, the blue progress bar just bobbing repeatedly to the left and right, without anything appearing within the gparted window.  A notification popped up with the following message:

Code:

Libparted Error
Invalid partition table on /dev/sda --wrong signature 0.

Because of this, I'm unable to resize the new disk's partitions 
Any help much appreciated ...

Mike

[m654321]

Solved it 

First, I can get into gparted by pressing the ignore button on the Libparted Error notification - silly me!
Within gparted, I then discovered the source of the Libparted Error: when I cloned the dual-boot system from the smaller to the larger drive, the extended partition remained at its former size.  So, I therefore extended this to the rest of the drive, which includes the new unallocated space on the larger drive.

Gparted now opens as normal, without any signature error or any other issues - problem solved - oh happy days ...