…or “What to do if you lose Mac OS after resizing your Windows Bootcamp partition”
TLDR; Scroll to the bottom of the post where I outline the steps I took to make my Mac partition bootable again without any data loss.
I was meant to spend this afternoon completing an assignment for my course due Thursday. Instead, I nearly lost all of my programming projects dating back to when I began to take programming seriously at age twelve. This is your typical "always have and check backups story"; something I thought I was immune to – until now, at least.
It began when I decided I needed to expand my Mac’s Windows 10 Bootcamp partition. I thought this would be an easy task; I’d shrink my APFS partition from Mac OS, as Disk Utility would be the beast utility to accomplish that task, and then expand my Windows partition from Windows, as I don’t trust Mac OS to expand NTFS. Shrinking the APFS partition went swimmingly, it took about 15 minutes and apart from Disk Utility freezing, seemed to complete without a hitch.
The next step was to expand my Bootcamp NTFS partition to fill the unallocated space on the SSD. I decided to undertake this task in Windows, rather than booting a Linux live USB. The first tool I tried was the built-in Windows Disk Management, however it quickly became apparent that it cannot resize a currently mounted partition, like the Windows C: drive. So off to the internet I went, in search of a partitioning tool that could somehow accomplish this task. I landed on EaseUS Partition Master, it was a program I had heard of before and it seemed to be fairly reputable. It advertised itself as a safe way to manage partitions. This turned out, in my case, to be false.