Partitions are not identified when ubuntu12.04 is installed in win7

Partitions are not identified when ubuntu12.04 is installed in win7

There was originally a Windows 7 7 on the computer. To develop it in the ubuntu environment, we had to install ubuntu.

In win7, the compressed volume makes room for 150 GB of space.

When installing ubuntu, I am prompted that there is no operating system on my computer.

Select a partition. Only the entire hard disk device is displayed, and the partition on the hard disk is invisible.

I found some information online and run the following command:

Sudo parted/dev/sda

Enter print

Tip:

It may be caused by a program that does not understand the GPT partition table. Or you have deleted the GPT table and now use the msdos partition table. Is this a GPT partition table?
Yes/No?

I entered Yes, but I still cannot see any partition information:

Model: ata hgst HTS725050A7 (scsi)
Disk/dev/sda: 500 GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Digit start: End size file system Name flag

Enter live as prompted by the online post, and then enter the following command:

Sudo dd if =/dev/zero of =/dev/sda bs = 1 count = 8 seek = 512

After installing ubuntu, you can see the partition.

Another reason may be that the last partition is out of the disk range, and ubuntu cannot identify the partition information.

You can modify the partition table.

For specific reasons, you can view the cause by using sudo parted/dev/sda print.