We always recommend delaying major macOS upgrades until Apple has had a chance to fix early bugs. The company has taken its first swing at the most egregious problems in macOS 10.13 High Sierra, not with the 10.13.1 update that we had expected, but with the “macOS High Sierra 10.13 Supplemental Update.” It’s highly focused, providing fixes for five specific problems:
It improves the robustness of the installer, which we hope will address reported issues with installations failing to complete.
It eliminates a problem that prevented the user from deleting email messages from Yahoo accounts in Mail.
It fixes an embarrassing mistake in Disk Utility — it turns out that if you set a hint in Disk Utility when creating an encrypted APFS volume, the password was stored as the hint, making it trivially easy to decrypt the volume. Oops!
It requires the user password when prompting for keychain access, which should prevent malicious applications from extracting passwords from the system keychain by bypassing the keychain access prompt with a synthetic click.
macOS High Sierra 10.13 Supplemental Update was 915 MB on my Retina iMac, and you can get it in the Updates screen of the App Store app.
Apple says that it has already built these fixes into new downloads of High Sierra, so if you haven’t yet updated, you won’t need the macOS High Sierra 10.13 Supplemental Update. But if you have already upgraded to High Sierra, we recommend installing this one sooner rather than later.