The Catalina 10.15.5 & 10.15.4 Supplemental Update is resetting the ComputerName, HostName & LocalHostName values back to default on some Macs.
UPDATE 7/15/20 – The macOS Catalina 10.15.6 update is live! The update fixes the ComputerName issue! mrmacintosh.com/whats-new-in-the-macos-catalina-10-15-6-update-19g73/
UPDATE: 7/01/20 – I just tested on 10.15.6 Beta 3 and the issue is fixed!!!
UPDATE: 5/29/20 – This issue is still definitely a problem with 10.15.5. I have multiple in house confirmations along with a bunch of reader reports.
UPDATE: 5/26/20 – I have now received 3 different reports of this same issue happening after installing the new macOS Catalina 10.15.5 Update. This issue does NOT happen on every Mac. The problem still seems to be intermittent. Please let Apple know that we need this fixed!!!
I would like to get back into writing more How-To articles. The thing is, reporting on issues like this help more people. I would love it if I could get a heads up on an issue that could cause problems in my environment. That’s the idea behind articles like this and my macOS System Status page.
Case in point is this article. Do you use the ComputerName, HostName or LocalHostName value for one of the following functions?
- MDM Computer Scope
- 802.1x Authentication
- Active Directory
- VPN
If you depend on the ComputerName or HostName for any of these services, it could wreak havoc for the user!
Let’s jump right in, I will give you you an overview of this issue.
Table of Contents
- 1. Affected macOS Build Version
- 2. Affected Mac Hardware
- 3. User Reports
- 4. Problem
- 5. The future of managing macOS Updates.
- 6. Should I block the 10.15.4 Supplemental Update?
- 7. Does Apple Know about this issue?
- 8. Links
1. Affected Mac Models
Unlike other issues, this one covers all Macs that are compatible with macOS Catalina that are on 10.15.4 (19E266).
2. Affected OS Versions
This issue affects only one macOS update.
- macOS Catalina 10.15.4 Supplemental Update (19E287) Released 4/8/20
NOTE: This issue does not happen with the updated 10.15.4 Combo & Delta updates.
3. User Reports
One of the very first reports was in a MacAdmins Channel. Let’s take a look at some of the reports.
Is anyone else having issues with macOS Catalina 10.15.4 Supplemental Update deleting log files form /var/log and changing the computer name to just the Mac model (eg iMac)
ckay
On a test Mac, I experienced this, and I filed feedback. Please file feedback, so they have an idea how widespread (or not) it is, and to help them solve it.
arekdreyer
Jamf is tracking this issue as well, this is definitely a thing.
benjermanjoel
4. Problem
This one is pretty cut and dry. If you set the ComputerName to a specific value, let’s say the SerialNumber, it will be reset back to factory default. In the case of a MacBook Pro the ComputerName would now be MacBook Pro.
Example Test
Fresh 2014 MacBook Pro erase & install with 10.15.4 (19E266). I then set the ComputerName and HostName to something different (Serial Number).
I used softwareupdate -iaR to install the 10.15.4 Supplemental Update.
Once the Mac Came back up, sure enough the ComputerName was MacBook Pro.
Most home users will never have to mess with this value. If you would like to check, open System Preferences > Sharing.
MacAdmins will set this value with one of the following ways.
- MDM Policy
- Script using
scutil
You can check the current value with scutil.
MacBook-Air:~ mrmacintosh$ sudo scutil --get ComputerName
MacBook Air
To set all three values you can run the commands below.
- 1.
sudo scutil --set ComputerName namehere - 2.
sudo scutil --set HostName namehere - 3.
sudo scutil --set LocalHostName namehere
This Jamf Article gives a great overview on how to manage this value.
https://www.jamf.com/jamf-nation/articles/148/updating-the-computer-name-of-managed-computers
5. The future of managing macOS Updates
This brings into focus the changes Apple is making to Software Update.
If you are unaware of the changes coming (as soon as 10.15.5), take a look at this excellent article by by Balmes Pavlov (@BaboDee2 on Twitter).
6. Should I block the 10.15.4 Supplemental Update?
Maybe
The supplemental update does not include any Security Related fixes. Take a look at the fix list below.
- Fixes an issue where Mac computers running macOS Catalina 10.15.4 could not participate in FaceTime calls with devices running iOS 9.3.6 and earlier or OS X El Capitan 10.11.6 and earlier
- Resolves an issue where you may repeatedly receive a password prompt for an Office 365 account
- Fixes an issue where MacBook Air (Retina, 13-inch, 2020) may hang in Setup Assistant or when disconnecting and reconnecting a 4K or 5K external display
- Resolves an issue where a USB-C port in your Mac may become unresponsive
If you need any of the above fixes, then I would say that you might need deploy it. You could also wait for a 10.15.4 Supplemental Update #2 or 10.15.5.
Deploy the update ONLY if you have a way to reset the ComputerName & HostName before the user can use the system!
You would need to deploy a LaunchDaemon that would execute a script to rename both values on load.
7. Does Apple Know about this issue?
Going by this post by Don, it’s not looking good as of last week.
Apple confirmed the
donmontalvo/private/var/log/issue (101063983106) but have not been able to replicate theComputerName/HostNameissue. They advised if anyone is able to replicate, open a ticket so they can look into it.
8. Links
Apple Discussion Forum
https://discussions.apple.com/thread/251260641
A few Jamf Customers who are having the issue.
MacAdmins
https://macadmins.slack.com/archives/CK7SUEH9N/p1586430026022800?thread_ts=1586430026.022800
https://macadmins.slack.com/archives/C0619KJQY/p1586436528427600
https://macadmins.slack.com/archives/CK7SUEH9N/p1586848916150400
10.15.4 supplemental update computername
I’ve upgraded twice (at least) to 10.15.5 without seeing this. Last night I foolishly assumed Apple had done something useful in 10.15.6, and updated. BOOM! They got me – about 15 terminal sessions “restored” with the old/deprecated/default hostname in the zsh prompt. The only way to correct this seems to be starting a new session!? When will these dolts at Apple get their heads in the game? I’ve better things to do with my time than clean up their defecation!
[See here for details](https://apple.stackexchange.com/questions/399244/catalina-upgrade-changes-host-name)
Hello Guys
i think its somthing with fresh mdm enrolled devices on os 10.15.4… i had som problems with the administrator account on this constellation.. i coundn’t change the boot device in the recovery mode -> error no administrator account aviable (but it had one :)) so my sugestion is on the upgrade from 10.15.4 to 10.15.5 he needs an administrative account and don’t have one.. so he loos ore reset these settings… that is what i guess happend.. because if i manualy install an 10.15.4 with an manual installed administrator account i had no problem to upgrad from 10.15.4 to 10.15.5… sorry iam new to apple.. was 20 years with windows working 🙂
greets
Thanks for this. I thought I must have broken something. I’ve now tested on three test machines and they all upgraded to 10.15.5 from 10.15.4 and they all changed name to iMac.
The last machine was just a clean machine – no management. No DEP – just ran all available updates
Here’s what software update reports for what was installed:
softwareupdate –history
Display Name Version Date
———— ——- —-
MRTConfigData 1.60 28/05/2020, 13:45:51
macOS Catalina 10.15.5 Update 28/05/2020, 13:20:04
MRTConfigData 1.60 15/05/2020, 08:03:45
XProtectPlistConfigData 2121 15/05/2020, 08:02:42
MRTConfigData 1.59 01/05/2020, 14:04:32
XProtectPlistConfigData 2120 01/05/2020, 14:03:27
XProtectPlistConfigData 2119 20/04/2020, 16:58:41
MRTConfigData 1.58 20/04/2020, 16:58:41
Gatekeeper Configuration Data 181 20/04/2020, 16:58:41
Typo:
“1. sudo scutil –set ComputerName namehere
2. sudo scutil –set ComputerName namehere”
Needed: s/ComputerName/HostName/
George, great catch! Fixed. Thanks