Missing Operating system after Yosemite update

Hit Escape only once.

This is a table to verify that the Testdisk output makes sense.

You will lose about 10Gb in the Gap.

Leave your Testdisk display and start a new Terminal Window. Please use the following steps.

If you see any error messages during the following steps, please stop and post back here with the error message. The following steps have values from your Testdisk output (and you can verify) in Steps 7 and 8.

Rebuild GPT4 using start/end offsets

1. Sudo gdisk /dev/rdisk0
2. P (print the full list of parts)
3. D (delete)
4. 4 (part 4)
5. N (new part)
6. 4 (part 4)
7. 752361472 - Start offset in bytes (start point for Bootcamp part)
8. +224411641 (Size offset as opposed to End offset)
9. 0700 (Windows part type)
10. P (print list of all parts just to see what changes will be made)
11. W (Write the new GPT)
12. Y (Yes! really write the new GPT)

This will delete and re-write the GPT partition info for /dev/disk0s4.

Rebuild MBR to match the new GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 6. Accept all other defaults that Gdisk offers.

1. Sudo gdisk /dev/disk0
2. P (Print list of parts)
3. R (Recover)
4. H (chooses Hybrid)
5. Partitions numbers to be hybridized: 2 3 4
6. Y (Good for GRUB question)
7. N (part 2 boot flag)
8. N (part 3 boot flag)
9. Y (part 4 boot flag make NTFS bootable partition)
10. W (Write the new MBR)
11. Y (Yes! write the new MBR)
12. Reboot

This is an example of the Q&A.

Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)

Enter an MBR hex code (default AF): Press Enter/Return

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #3 (MBR partition #3)

Enter an MBR hex code (default AB): Press Enter/Return

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #4)

Enter an MBR hex code (default 07): 07

Set the bootable flag? (Y/N): Y

Test 1 - Does Bootcamp Volume show up in Finder?

Test 2 - Can you see files in Bootcamp Volume?

Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?

Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.

There is an example below for using defaults. 😉

Yes, please reboot and test.

I assume it is working as you have marked it. Please ensure you have backups of OSX and Windows on separate external disks and keep these as a baseline.