Recover BootCamp Partition Data

[anc8800]

Was using OS X Mountain Lion along side Windows 8 installed using BootCamp Assistant, today I upgraded to OS X Mavericks and I cannot boot into windows anymore. The partition does not even appear in Disk Utility...

Result of sudo fdisk /dev/rdisk0:

Disk: /dev/rdisk0 geometry: 60801/255/63 [976773168 sectors]
Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
1: EE 1023 254 63 - 1023 254 63 [ 1 - 409639] <Unknown ID>
2: AF 1023 254 63 - 1023 254 63 [ 409640 - 588038448] HFS+
3: AB 1023 254 63 - 1023 254 63 [ 588448088 - 1269536] Darwin Boot
4: 0C 1023 254 63 - 1023 254 63 [ 869351424 - 107421696] Win95 FAT32L

Result for sudo gpt -r -vv show disk0

gpt show: disk0: mediasize=500107862016; sectorsize=512; blocks=976773168
gpt show: disk0: Suspicious MBR at sector 0
gpt show: disk0: Pri GPT at sector 1
gpt show: disk0: Sec GPT at sector 976773167
start size index contents
0 1 MBR
1 1 Pri GPT header
2 32 Pri GPT table
34 6
40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
409640 588038448 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC
588448088 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
589717624 279633800
869351424 107421696 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
976773120 15
976773135 32 Sec GPT table
976773167 1 Sec GPT header

Please help critical data at risk, cannot afford any data loss.

 

[Quackers]

Can you see the Bootcamp partition in a Finder window?

This has happened because at some time in the past (but since Bootcamp installed Windows) you have resized a partition. This is not allowed with a Bootcamp partition.
Now that you have upgraded to Mavericks the installer (not finding what it expected) has over-written the MBR of the drive and consequently Windows will not now boot.

If the partition resizing was done some time ago the data may have been over-written.

You have two choices, as I see it.
You can try to repair this, which will involve a lot of work, using testdisk to find the old Windows partition and recovering it, then using gdisk to create a new hybrid MBR.
This is a lot of work and there is no guarantee of success.

The other option would be the standard Apple way of dealing with this situation - i.e. boot from the recovery HD, completely wipe that hard drive and start again - re-installing OSX from scratch.