What you need to know about the HFS+ file system, so you can understand error reports and how to repair it using Disk Utility and other tools.
APFS
What you need to know about disk formatting using the GUID Partition Table (GPT) to understand its problems and how to repair it.
One was just a bit wonky, the other has made a mess of many who installed the update. So what went wrong?
Concentrate on Time Machine backups, scripts, secondary updates, and whether you still have to retain access to 32-bit software. Some hints.
One new tool to list capacities on mounted volumes, the other to deliver detailed information on keychains.
How to store a 400 GB sparse bundle on a volume which only has 200 GB free space – provided that you don’t actually use the space that isn’t there.
Disk Utility can’t image APFS volumes, and normally returns an error if you try to image a container. Here’s the workaround.
It’s got to be better than Catalina, so why not upgrade when it first comes out? Here are some suggestions to help you make your decision.
A complete guide to the structure and layout of APFS startup disks from High Sierra to Big Sur (Intel), together with tear-out PDF charts.
If something goes wrong with Catalina’s boot Volume Group, it seems there’s no way to repair it, or change the Data volume. Or is there?
The Eclectic Light Company 