Windows 10 Automatic Startup Repair Boot Loop

I have received to error messages when trying to boot to Windows 10.

* Inaccessible boot drive * Windows couldn't repair your PC

I have tried fixmbr, fixboot, and reubildbcd and don't know what else to do. The drive is accessible and sounds fine.

Willing to try almost anything except wiping the drive and reinstalling.

edit- I should note that this 2 TB drive has 4 partitions.

* System Reserved (100 MB)

* Recovery (I Think) (~500 MB)

* OS (800 GB)

* Data (1.1 TB)

I'm trying to fix this for a family member and this is how they structured the drive.