Just updated to macOS Catalina 10.15.4, and immediately one of my two external Time Machine drives, both of which are 100% (verified neither are experiencing any mechanical problems), stopped being recognized by my Mac, and when I tried to reformat it using Disk Utility, using HFS+ Encrypted (Mac OS Extended (Journaled, Encrypted)) option, I get the following readout:
Erasing “WDC WD10 02FAEX-00Y9A0 Media” (disk2) and creating “Untitled” Unmounting disk Creating the partition map Waiting for partitions to activate Formatting disk2s2 as Mac OS Extended (Journaled) with name Untitled Initialized /dev/rdisk2s2 as a 931 GB case-insensitive HFS Plus volume with a 81920k journal Mounting disk Unmounting disk2s2 Touching partition type on disk2s2 Adding disk2s2 to Logical Volume Group Creating Core Storage Logical Volume Group Switching disk2s2 to Core Storage Waiting for Logical Volume Group to appear Discovered new Logical Volume Group “57A79610-663C-4C4F-9A7D-21160B977902” Waiting for Logical Volume to appear Formatting file system for Logical Volume newfs_hfs: WriteBuffer: pwrite(3, 0x1017f4000, 1048576, 19927040): Device not configured newfs_hfs: write (sector 38920): Invalid argument Mounting disk Could not mount disk3 after erase File system formatter failed. : (-69832) Operation failed…
I've tried attaching 2 other known good drives, all exact same results. It appears Apple broke something with the .4 update, as this was not an issue, ever, in any previous version of macOS for me.
Oddly, I can use APFS encrypted, but not HFS+ Encrypted.