Language & Region -> "There was an error in Language & Region preferences."

1 - Restart in Safe Mode. This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts. The boot up will be slow and can take some time - Normal.

2 - Does the issue present in this mode ?

3 - Sometimes a Safe Boot followed by a Normal Boot will just put things right.

4 - If not - there could be something in the main User Account playing up. To further isolate this - Set up users, guests, and groups on Mac. Then log out of the Main User account and log into the dummy account and test again if the issue persists.

5 - If the issue is present in the dummy account - then, this appears to be a System Wide issue on the computer.

6 - If after performing each of the above steps is the order that have been presents  and still have issues - please advise for possible further assistance.

Since the issue Is Occurring in Safe Mode and Regular Mode but in a Guest Account - it appears the Issue is in the Main User Account

Understand, we are all working Remotely from all around the world. Therefore, we do not have the On-Hands experience the User ( you ) has with this computer.

The below suggestion is the next best thing to us having actual On-Hand to this computer.

7- Suggest downloading the Application Etrecheck directly from a well Respected ASC Contributor. And Safe to use.

The application is free or paid from added features. 

Run the application with Full Disc Access ( Security & Privacy - Full Disc Access ).

It will take a Snap Shot -  both the hardware and software.

 The Report will Not Reveal Any Personal Information. 

Post back the Full Report - copy and paste - using the Additional Text Icon ( 3rd Icon to last )

We can have a look at the report for possible issues and may have possible suggestions to resolve the issues.

ccvectorworker wrote:

I have never heard of this application and I am not comfortable running it on my company's hardware to resolve this issue.

I would like an official Apple Support response to this issue if possible. It is clearly a bug in the OS components, possibly related to permissions. It began happening after OS security updates were applied.

I am seeing some error logging in the console related to the xpc service in the Localization.prefPane.

Here are the earliest errors I see:

error 11:21:06.056157-0700 runningboardd Could not rationalize xpc service at: /System/Library/PreferencePanes/Localization.prefPane/Contents/XPCServices/Localization.remoteservice.xpc/Contents/MacOS/Localization.remoteservice

error 11:21:06.128923-0700 Localization.remoteservice cannot open file at line 45530 of [9ff244ce07]

error 11:21:06.128961-0700 Localization.remoteservice os_unix.c:45530: (2) open(/var/db/DetachedSignatures) - No such file or directory

I will also investigate further the difference using different accounts. Perhaps the Guest account did not reproduce the problem because it uses only temporary file storage and I did not actually attempt to change any language settings.

Q -" I have never heard of this application and I am not comfortable running it on my company's hardware to resolve this issue. "

A - Personal preferences though, it has been reported where even Apple Support have turned to this very Application to Trouble Shoot clients computers

Q- " I would like an official Apple Support response to this issue if possible. It is clearly a bug in the OS components, possibly related to permissions. It began happening after OS security updates were applied. "

A - Then sorry to make it known, this is not the place to expect Apple the Company to offer such a request

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A - Apple Support Communities is a place to help each other get the most out of their Apple products and services.

To make this a community where all members feel comfortable to ask and answer questions, follow these guidelines.

1. Help us show respect to all. Most answers are provided by other Communities users just like you—not by Apple.

A - To supply a possible direct line to Apple for the above request Feedback