Thank you for your infos!
Lokks like, that you have a Laptop using UEFI (extensible firmware interface).
That's why your GPT disk looks correct.
UEFI-Laptops are coming more and more.
Something where I've to get used to.
I've had a look into your log file.
Your GPT partition table contains only one EFI-GPT partition using your whole disk.
500 GB / 465 GiB - CHS 60801 255 63
Current partition structure:
1 P EFI GPT 0 0 2 60801 80 63 976773167
No partition is bootable
Strange thing is, that your disk management console displays all your partitions.
That's why is difficult for me to determine to write your GPT partition table again.
Only in case, if it's necessary.
Quick Search finds your partition structur and all labels of your partitions are available.
But your [Windows8_OS]-partition looks faulty!
Failed to calculate number of free MFTs: Input/output error.
file_pread(10,16,buffer,12529664(779/238/36)) ReadFile Data error (cyclic redundancy check).
file_pread(10,16,buffer,12529672(779/238/44)) ReadFile Data error (cyclic redundancy check).
file_pread(10,1,buffer,12529672(779/238/44)) ReadFile Data error (cyclic redundancy check).
NTFS filesystem need to be repaired.
You're able to list your files.
I recommend before you run any chkdsk and and any other systemtools aigainst your disk, you should copy/backup your files first.
When you list your files, at the bottom of your screen you'll find all the copy commands.
You should use another healthy partition or disk to have a try to copy your data to.
If you'd like to change directories or disks, just mark that two dots at the upper area of the testdisk display
and hit enter.
You'll get one directory up until you get to your disk selection.
Choose your appropriate disk and folder.
Standard folder is normally the testdisk folder.
Mostly, you'll find your important files like music, pictures etc.. under users and your profile.
So you can avoid to copy unnecessary files.
To copy broken or damaged files can cause problems or hang?
If you were backing up your data you can try to run chkdsk against your affected partition [Windows8_OS].
The option would be:
chkdsk driveletter: /r
It's a try to repair your file system.
As long as you'd like to recover data it's not recommended to modify or change anything to your file system.
Fiona