Why are Network Location DNS settings not persistent (after reboot)?

Do a backup, preferably 2 backups on 2 separate drives.

Quit System Preferences.

Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J. When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder. Select Library. Then go to Preferences/com.apple.systempreferences.plist. Move the .plist to your desktop.

Restart the computer, open the application, and test. If it works okay, delete the plist from the desktop.

If the application is the same, return the .plist to where you got it from, overwriting the newer one.

Thanks to leonie for some information contained in this.

Try setting up another admin user account to see if the same problem continues. Also try the Safe Mode.

Isolating an issue by using another user account

Safe Mode - About El Capitan
also Sierra

Safe Mode Startup – El Capitan. also Sierra

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor. Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown.

Etrecheck – System Information

I have much the same problem except they are not even persistent after I save, apply and close network preferences. Is true for both Ethernet and WiFi. I have removed Preferences/com.apple.systempreferences.plist and restarted. Still the same result. I keep a second system on an external drive and it is at the same MacOS level as my main drive. It is NOT affected. I therefore believe the problem is NOT hardware but in the OS on my primary boot drive.

One option is to reformat the internal hard drive and do a clean install. Before I go nuclear, is there something else that I should try?

System Version: macOS 10.13.4 (17E199)

iMac (Retina 5K, 27-inch, Late 2014), i7, 4 GHz, 32 GB memory

Worked in safe boot mode. Ran (and purchased software) the Etrecheck software. Report below:

EtreCheck version: 4.1.4 (4A203)

Report generated: 2018-04-09 00:59:04

Download EtreCheck from https://etrecheck.com

Runtime: 3:47

Performance: Good

Problem: Other problem

Major Issues: None

Minor Issues:

These issues do not need immediate attention but they may indicate future problems.

Apps crashing- There have been numerous app crashes.

Apps with heavy CPU usage- There have been numerous cases of apps with heavy CPU usage.

Clean up- There are orphan files that could be removed.

Unsigned files- There is unsigned software installed. They appear to be legitimate but should be reviewed.

System modifications- There are a large number of system modifications running in the background.

Hardware Information:

iMac (Retina 5K, 27-inch, Late 2014)

iMac Model: iMac15,1

1 4 GHz Intel Core i7 (i7-4790K) CPU: 4-core

32 GB RAMAt maximum

BANK 0/DIMM0

8 GB DDR3 1600 ok

BANK 1/DIMM0

8 GB DDR3 1600 ok

BANK 0/DIMM1

8 GB DDR3 1600 ok

BANK 1/DIMM1

8 GB DDR3 1600 ok

Video Information:

AMD Radeon R9 M295X - VRAM: 4096 MB

iMac

LG ULTRAWIDE 2048 x 864 @ 60 Hz

Drives:

disk0 - APPLE HDD ST3000DM001 3.00 TB (Mechanical)

Internal SATA 6 Gigabit Serial ATA

disk0s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk0s2 [Core Storage Container] 1.38 TB

disk2 - Macintosh HD (Journaled HFS+) [Fusion Drive] 1.50 TB

disk0s3 - Recovery HD (Journaled HFS+) [Recovery] 650 MB

disk0s4 - M************* (Journaled HFS+) 1.00 TB

disk0s5 - U******d (Journaled HFS+) 614.73 GB

disk1 - APPLE SSD SD0128F 121.33 GB (Solid State - TRIM: Yes)

Internal PCI 5.0 GT/s x2 Serial ATA

disk1s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk1s2 [Core Storage Container] 120.99 GB

disk2 - Macintosh HD (Journaled HFS+) [Fusion Drive] 1.50 TB

disk1s3 - B*******X [Recovery] 134 MB

disk3 - Crucial_CT525MX300SSD1 525.11 GB (Solid State - TRIM: No)

External Thunderbolt 6 Gigabit Serial ATA

disk3s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk3s2 262.45 GB

disk7s1 - SSD (APFS) 262.45 GB 110.46 GB

disk7s2 - Preboot (APFS) [APFS Preboot] 262.45 GB 26 MB

disk7s3 - Recovery (APFS) [Recovery] 262.45 GB 520 MB

disk7s4 - VM (APFS) [APFS VM] 262.45 GB 20 KB

disk3s3 262.45 GB

disk6s1 - C***e (APFS) 262.45 GB 85.54 GB

disk4 - WDC WD2001FASS-00W2B0 2.00 TB (Mechanical)

External Thunderbolt 3 Gigabit Serial ATA

disk4s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk4s2 - C*******D (Journaled HFS+) 210.28 GB

disk4s3 - P*******************p (Journaled HFS+) 900.00 GB

disk4s4 - W*****************X (Journaled HFS+) 888.86 GB

disk5 - WDC WD2001FASS-00U0B0 2.00 TB (Mechanical)

External Thunderbolt 3 Gigabit Serial ATA

disk5s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk5s2 1.00 TB

disk11s1 - A*****************7 (APFS) 1.00 TB 110.72 GB

disk5s3 999.72 GB

disk13s1 - A*****************************p (APFS) 999.72 GB 314.22 GB

disk8 - WDC WD40EZRZ-00WN9B0 4.00 TB (Mechanical)

External Thunderbolt 6 Gigabit Serial ATA

disk8s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk8s2 - C******************D (Journaled HFS+) 2.00 TB

disk8s3 - Recovery HD (Journaled HFS+) [Recovery] 650 MB

disk8s4 - C********************2 (Journaled HFS+) 2.00 TB

disk9 - Western Digital My Book 1230 4.00 TB

External USB 5 Gbit/s

disk9s1 - EFI [EFI] 315 MB

disk9s2 - T************1 (Journaled HFS+) 4.00 TB

disk10 - HGST G-DRIVE 4.00 TB

External USB 5 Gbit/s

disk10s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk10s2 - T************3 (Journaled HFS+) 4.00 TB

disk12 - Western Digital My Book 25EE 8.00 TB

External USB 5 Gbit/s

disk12s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk12s2 - T************4 (Journaled HFS+) 8.00 TB

Mounted Volumes:

disk0s4 - M************* 1.00 TB (361.15 GB free)

Journaled HFS+

Mount point: /Volumes/M*************

disk0s5 - U******d 614.73 GB (614.11 GB free)

Journaled HFS+

Mount point: /Volumes/U******d

disk2 - Macintosh HD [Fusion Drive] 1.50 TB (346.86 GB free)

Journaled HFS+

Mount point: /

disk4s2 - C*******D 210.28 GB (14.23 GB free)

Journaled HFS+

Mount point: /Volumes/C*******D

disk4s3 - P*******************p 900.00 GB (589.45 GB free)

Journaled HFS+

Mount point: /Volumes/P*********************1

disk4s4 - W*****************X 888.86 GB (786.43 GB free)

Journaled HFS+

Mount point: /Volumes/W*******************1

disk6s1 - C***e 262.45 GB (176.77 GB free)

APFS

Mount point: /Volumes/C***e

Encrypted

disk7s1 - SSD 262.45 GB (151.31 GB free)

APFS

Mount point: /Volumes/SSD

disk8s2 - C******************D 2.00 TB (115.94 GB free)

Journaled HFS+

Mount point: /Volumes/C******************D

disk8s4 - C********************2 2.00 TB (223.84 GB free)

Journaled HFS+

Mount point: /Volumes/C********************2

disk9s2 - T************1 4.00 TB (2.14 TB free)

Journaled HFS+

Mount point: /Volumes/T************1

disk10s2 - T************3 4.00 TB (1.15 TB free)

Journaled HFS+

Mount point: /Volumes/T************3

disk11s1 - A*****************7 1.00 TB (889.27 GB free)

APFS

Mount point: /Volumes/A*****************7

disk12s2 - T************4 8.00 TB (6.61 TB free)

Journaled HFS+

Mount point: /Volumes/T************4

disk13s1 - A*****************************p 999.72 GB (685.30 GB free)

APFS

Mount point: /Volumes/A*****************************p

Network:

Interface en0: Ethernet

One IPv4 address

Interface en6: iPad

Interface en1: Wi-Fi

802.11 a/b/g/n/ac

One IPv4 address

Interface bridge0: Thunderbolt Bridge

Interface en5: iPhone

Interface en4: Bluetooth PAN

iCloud Quota: 163.16 GB available

System Software:

macOS High Sierra 10.13.4 (17E199)

Time since boot: Less than an hour

System Load: 2.79 (1 min ago) 11.17 (5 min ago) 7.38 (15 min ago)

Security:

Unsigned Files:

Launchd: ~/Library/LaunchAgents/com.valvesoftware.steamclean.plist

Executable: ~/Library/Application Support/Steam/SteamApps/steamclean

Details: Exact match found in the whitelist - probably OK

Launchd: /Library/LaunchDaemons/com.formacx.SimDaemon.plist

Executable: /Library/Application Support/SimBooster/SimDaemon -load

Details: Exact match found in the whitelist - probably OK

Kernel Extensions:

/Library/Application Support/Logitech.localized/Logitech Options.localized

[Not Loaded] LogiMgrDriver.kext (Logitech Inc., 6.80.1 - SDK 10.12)

/Library/Application Support/Symantec/AntiVirus

[Loaded] SymAPComm.kext (100.1f1 - SDK 10.8)

/Library/Extensions

[Loaded] G13Joystick.kext (Logitech Inc., 2.0 - SDK 10.10)

[Not Loaded] LogiGamingMouseFilter.kext (Logitech Inc., 1.0 - SDK 10.10)

[Not Loaded] LogiWheelDriver.kext (Logitech Inc., 1.0 - SDK 10.10)

[Loaded] LogiKextChecker.kext (Logitech Inc., 1.0 - SDK 10.10)

[Loaded] SymInternetSecurity.kext (Symantec, 5.2.2 - SDK 10.11)

[Loaded] SymIPS.kext (Symantec, 3.5.1 - SDK 10.8)

[Loaded] ndcengine.kext (Symantec, 1.0 - SDK 10.8)

/System/Library/Extensions

[Not Loaded] Belcarra.USBLAN_netpart.kext (3.1.1 - SDK 10.6)

[Not Loaded] Belcarra.USBLAN_usbpart.kext (3.1.1 - SDK 10.6)

[Not Loaded] RemoteControl.USBLAN_usbpart.kext (3.1.1 - SDK 10.7)

[Not Loaded] LogiWheelForceFeedback.kext (1.0 - SDK 10.10)

/System/Library/Extensions/2.2.0/Belcarra.USBLAN_netpart.kext/Contents/Plug-Ins

[Not Loaded] Belcarra.USBLAN_netpart.kext (1.6.3)

/System/Library/Extensions/2.2.0/Belcarra.USBLAN_usbpart.kext/Contents/Plug-Ins

[Not Loaded] Belcarra.USBLAN_usbpart.kext (1.6.3)

/System/Library/Extensions/2.2.0/RemoteControl.USBLAN_usbpart.kext/Contents/Plug -Ins

[Not Loaded] RemoteControl.USBLAN_usbpart.kext (1.6.2)

System Launch Agents:

System Launch Daemons:

Launch Agents:

Launch Daemons:

User Launch Agents:

User Login Items:

Logitech Gaming Software Application

(/Applications/Logitech/Logitech Gaming Software.app)

Dyn Updater Application (Dynamic Network Services Inc.

(/Applications/Dyn Updater.app)

ExpressVPN Application (ExprsVPN LLC

(/Applications/ExpressVPN.app)

CCC User Agent Application (Bombich Software, Inc. - installed 2018-03-06)

(/Applications/Carbon Copy Cloner.app/Contents/Library/LoginItems/CCC User Agent.app)

Mail Application (Apple, Inc.

(/Applications/Mail.app)

Garmin Express Application (Garmin International

(/Applications/Garmin Express.app)

Message+ Application (Mac App Store

(/Applications/Message+.app)

Recipes4.fmp12 FileMaker Document

(~/Dropbox/Bread Database/Recipes4.fmp12)

Deliveries Application (Mac App Store

(/Applications/Deliveries.app)

Safari Application (Apple, Inc.

(/Applications/Safari.app)

Logitech Gaming Software Application

(/Applications/Logitech/Logitech Gaming Software.app)

Parallels Toolbox Application (Parallels International GmbH

(/Applications/Parallels Toolbox.app)

Dropbox Application (Dropbox, Inc.

(/Applications/Dropbox.app)

EvernoteHelper SMLoginItem (Evernote - installed 2018-03-26)

(/Applications/Evernote.app/Contents/Library/LoginItems/EvernoteHelper.app)

1Password mini SMLoginItem (AgileBits Inc. - installed 2018-03-16)

(/Applications/1Password 6.app/Contents/Library/LoginItems/2BUA8C4S2C.com.agilebits.onepassword4-helper. app)

2Do Helper SMLoginItem (Mac App Store - installed 2018-02-01)

(/Applications/2Do.app/Contents/Library/LoginItems/EKT6323JY3.com.guidedways.Tod oMac.Helper.app)

LCLauncher SMLoginItem (Mac App Store - installed 2017-02-01)

(/Applications/Light Control.app/Contents/Library/LoginItems/LCLauncher.app)

GamePadCompanionLauncher SMLoginItem (Mac App Store - installed 2017-02-01)

(/Applications/GamePad Companion.app/Contents/Library/LoginItems/GamePadCompanionLauncher.app)

Deliveries Express SMLoginItem (Mac App Store - installed 2017-12-18)

(/Applications/Deliveries.app/Contents/Library/LoginItems/Deliveries Express.app)

ColorSnapper2Helper SMLoginItem (Mac App Store - installed 2017-12-18)

(/Applications/ColorSnapper2.app/Contents/Library/LoginItems/ColorSnapper2Helper .app)

Internet Plug-ins:

AdobeAAMDetect: 3.0.0.0 (installed 2018-02-21)

FlashPlayer-10.6: 29.0.0.113 (installed 2018-03-13)

QuickTime Plugin: 7.7.3 (installed 2018-03-27)

AdobePDFViewerNPAPI: 17.012.20098 (installed 2018-02-25)

AdobePDFViewer: 18.011.20038 (installed 2018-02-25)

Flash Player: 29.0.0.113 (installed 2018-03-13)

Flip4Mac WMV Plugin: 3.3.7.2 (installed 2015-10-24)

npwViewer_turn: Unknown (installed 2016-08-18)

SmartCamFinder: SmartCamFinder 1.0.0.0 (installed 2014-12-08)

User Internet Plug-ins:

Picasa: 1.0 (installed 2015-10-13)

Safari Extensions:

3rd Party Preference Panes:

Backblaze Backup (installed 2018-04-07)

Flash Player (installed 2018-02-23)

Flip4Mac WMV (installed 2015-10-24)

Logi Options Launcher (installed 2018-03-03)

MySQL (installed 2016-02-01)

Symantec QuickMenu (installed 2016-09-30)

TechTool Protection (installed 2017-12-23)

Time Machine:

Skip System Files: No

Mobile backups: No

Auto backup: Yes

Volumes being backed up:

M************* : Disk size: 1.00 TB - Disk used: 638.85 GB

Macintosh HD: Disk size: 1.50 TB - Disk used: 1.15 TB

Destinations:

T************1 [Local]

Total size: 4.00 TB

Total number of backups: 45

Oldest backup: 2017-12-27 06:58:43

Last backup: 2018-04-08 21:09:07

T************4 [Local] (Last used)

Total size: 8.00 TB

Total number of backups: 4

Oldest backup: 2018-04-08 00:54:45

Last backup: 2018-04-08 22:00:04

T************3 [Local]

Total size: 4.00 TB

Total number of backups: 87

Oldest backup: 2016-12-24 17:19:28

Last backup: 2018-04-09 00:24:30

Top Processes by CPU:

Top Processes by Memory:

Top Processes by Network Use:

Top Processes by Energy Use:

Virtual Memory Information:

Software Installs (past 30 days):

Clean up:

~/Library/LaunchAgents/com.skype.skype.shareagent.plist

/Applications/Skype.app/Contents/Library/LaunchServices/com.skype.skype.shareage nt.bundle/Contents/MacOS/com.skype.skype.shareagent

Executable not found

/Library/LaunchDaemons/com.twocanoes.bootrunnerprefpanehelper.plist

/Library/PrivilegedHelperTools/com.twocanoes.bootrunnerprefpanehelper

Executable not found

Diagnostics Information (past 7 days):

2018-04-09 00:43:15 iStatServerDaemon Crash (2 times)

2018-04-08 21:55:45 Firestorm-Releasex64.app CPU (27 times)

2018-04-08 01:32:25 SymDaemon CPU (2 times)

2018-04-07 14:37:35 Adobe CEF Helper.app Crash (19 times)

2018-04-07 13:47:32 TechTool Pro 9.app Hang (2 times)

2018-04-06 23:44:27 GamePad Companion.app Crash (13 times)

2018-04-04 17:42:00 Stamps.com Connect.app Crash (once)

End of report

I would uninstall Symantec. It tends to interfere with the computer's operation while providing minimal to no benefit unless you work with Windows files. Most long time posters recommend not using antivirus software or cleaning software such as CleanMyMac.

Symantec Uninstaller

Alas, that didn't fix it. But it had occurred to me as well.

Right after I got this machine, the Fusion drive became unlinked. Apple had just removed fixing Fusion drives with Disk Utility. After considerable research, I managed to get corestoreage to relink drive. I created two and now three partitions with the OS on the fused partition, which is now too small.

Since I cannot expand the first partition, I have been planning to reformat the drive as a single partition anyway. I am thinking of removing any apps that I don't use, take a couple of backups, and then do a reformat and TimeMachine install of a fresh system. I have a Carbon Copy Cloner back up of both drives as well and three active Time Machine Disks plus BackBlaze. Yes, I have been burned. 😁

Failing that, I will do a clean install (ugh).

Does this make sense to you?

And thanks for ALL you help.

You are welcome. That does make sense.

TimeMachine Install didn't work. Now, long, drawn out grunge work ahead.

What happened when you tried? Did you try a clone restore?

Have done both. I am going to try removing Preferences/com.apple.systempreferences.plist one more time and then Armageddon. 😢

Good luck.