Q: Bootcamp panic

Can you hold Option while booting to boot into Mac OS, or does the computer kernel panic / show a folder?

Turn the computer off by holding the power button, then turn the computer on and immediately hold "Option," not Command.

See if Macintosh HD appears. If it does, try booting to the Mac side. Then open Boot Camp Assistant and try to remove Windows. This will repartition the hard drive.

Boot Camp: Remove Windows from your Mac

Any partitioning activity on the Windows side will cause issues. Any Mac older than 2015 uses a Hybrid MBR and Windows has no idea that you are actually sitting on a GPT disk. Please boot into Internet Recovery (not Local Recovery) using Command+Opt+R.

If this does not work, please see How to install OS X on an external drive connected to your Mac - Apple Support and use it to install OSX on an external disk so your internal disk can be examined. Your current internal disk was corrupted by the Windows side tool/disk management and is now a MBR disk. OSX will not boot from a MBR-only disk. It needs a GPT/EFI boot.

Apologies for jumping in, Pmintz25 .

It may be possible to change the disk back to GPT with Hybrid MBR and make things work. It also depends on what changes were made to NTFS by the tool.

Did you use Windows Disk Management, or a third-party tool?

Please install OSX on an external disk from the link I posted earlier. Please also install GPT Fdisk from https://sourceforge.net/projects/gptfdisk/ on this external disk OSX installation. Do not modify the internal disk in any way.

Internet Recovery offers the OSX version the Mac was originally shipped with - OS X: About OS X Recovery - Apple Support .

Which version of OS X is installed by OS X Recovery?

• If you use the Recovery System stored on your startup drive to reinstall OS X, it installs the most recent version of OS X previously installed on this computer.
• If you use Internet Recovery to reinstall OS X, it installs the version of OS X that originally came with your computer. After installation is finished, use the Mac App Store to install related updates or later versions of OS X that you have previously purchased.

Upgrade ML to match the version that you last had on your internal disk. Minor version differences of 10.11 are fine.