External Raid hard drive read only mode After upgrade to 26.4 Cannot rebuild drives in any format other than APFS or EXFAT, any of the format will not mount.
Update Tahoe 26.4 issue
Isn't this a known issue in the release notes?
HFS external media might fail to mount automatically. (168672160)
Workaround: For macOS only, use CLI tool diskutil mount to attach the relevant disk device.