I have a 13-inch 2015 model Macbook Pro that has macOS High Sierra 10.13.3 installed on it and I was going to install Windows 8.1 manually since Bootcamp assistant failed. What I did was going to disk utility and creating a partition. It failed with the APFS error 49153 and my left space in Disk Utility immediately turned gray, which is the color for "Other Disk Partitions". I thought it was a temporary problem so I restarted Disk Utility, but it stayed the same. I then realized right under "Other Disk Partitions", it said -578,1MB, which is definitely not right. I am not sure what to do right now, and I am afraid to shut down my computer as it might not boot again. Is there any way to fix this?