partition lost

[lcsh]

can any one help me how to find the lost partitions. My hard disk size was 512 gb but it reduced to 476 gb after i run the hp recovery. 

[WAWood]

@lcsh 

If a partition was indeed "lost" then there will be unallocated space on your drive where the partition used to be.  IF, on the other hand, it has been overwritten, there is probably no way to get it back.

To see the partitions on your drive, enter "create and format" in the search area, and select Create and format hard disk partitions.  This will open the Disk Managment window and you will see all the partitions listed.

Please post back here what you see.

[lcsh]

Thanks WAWood, there is a misunderstanding here. I run the HP recovery twice and I got my hard disk about 40 GB smaller than it was. That is because I installed Ubuntu as well. but the recovery just format the windows partition only, that made the other partitions disappeared. After the recovery I can only see the new partitions in the new formatted disk which is smaller than it should be. I tried 'Testdisk' and 'Diskgenius' they both can see some extra space which was lost outside the current hard disk, but once I do something with it, the windows can not reboot because the partition table has been changed.  That is the reason I did the recovery twice. Do you have any further suggestion? best !

[WAWood]

You didn't mention Ubuntu earlier, so now I am confused.

Which partitions are missing -- Windows partitions or Ubuntu partitions?

[lcsh · Accepted solution]

Thanks WAWood,  I think I've found the reason why my hard disk get smaller after recovery now. The hard disk producers use decimal system to assign their products' size but computer use binary system to measure the hard disk. That makes the hard disk 7 percent smaller than what we expect. No partition missing in my hard disk now:) Do you agree with this?  Thanks a lot again. All the best!  

[WAWood]

@lcsh 

You are correct in that there are two slightly different methods for measuring disk size.  One uses units of 1000, the other uses units of 1024 -- so for example, a disk advertised as 1000GB, when formatted, is shown as 931GB. This is not a loss of 70GB, but rather, a difference in two measuring systems.