Cannot boot in Windows 8.1 anymore (after making some changes in both systems)

Question

Problem: I cannot boot in the Windows 8.1 partition created with Bootcamp anymore. When I try to do that, the system displays the grey screen then goes into a command line mode similar with MS-DOS and asks for inserting a disk (it reports no bootable drive).
Possible causes:
- I disabled the Bootcamp process in the Notification area in the Windows 8.1 systray
- I created a new partition in OS X on which I installed an older OS X version I still need to use (Mt Lion)

Answer 1

BroFlav wrote:
Can you tell me what exactly I should do in gdisk after merging the OS X partitions with their respective Recovery partitions?
Thanks, in advance.
Once you have EFI, Yosemite HD, Lion HD and Bootcamp, use the following steps. Your values will be different then this example. Use defaults except the boot ability flag for the last Bootcamp partitions to be 'y'.
sudo gdisk /dev/disk0
GPT fdisk (gdisk) version 0.8.10
Warning: Devices opened with shared lock will not have their
partition table automatically reloaded!
Partition table scan:
  MBR: hybrid
  BSD: not present
  APM: not present
  GPT: present
Found valid GPT with hybrid MBR; using GPT.
Command (? for help): p
Disk /dev/disk0: 490234752 sectors, 233.8 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 59BDFEEB-1EB4-4529-94FE-3CBC2C3CD513
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 490234718
Partitions will be aligned on 8-sector boundaries
Total free space is 2604 sectors (1.3 MiB)
Number  Start (sector)    End (sector)  Size       Code  Name
   1              40          409639   200.0 MiB   EF00  EF
   2          409640       401060383   191.0 GiB   AF05  Macintosh HD
   3       401060384       402329919   619.9 MiB   AB00  Re
   4       402331648       490233848   41.9 GiB    0700  Microsoft basic data
Command (? for help): r
Recovery/transformation command (? for help): h
WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one,
just hit the Enter key at the below prompt and your MBR partition table will
be untouched.
Type from one to three GPT partition numbers, separated by spaces, to be
added to the hybrid MBR, in sequence: 2 3 4
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): AF
Set the bootable flag? (Y/N): n
Creating entry for GPT partition #3 (MBR partition #3)
Enter an MBR hex code (default AB): AB
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
Recovery/transformation command (? for help): w
Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!
Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/disk0.
Warning: Devices opened with shared lock will not have their
partition table automatically reloaded!
Warning: The kernel may continue to use old or deleted partitions.
You should reboot or remove the drive.
The operation has completed successfully.
Now Reboot and verify the output of fdisk again.