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User profile for user: -Doug
-Doug Author
User level: Level 1
4 points

HD Read & Write permissions

I have acquired an older iMac which had been erased/wiped/cleaned prior to sale, as normal. A tech installed the latest version of Catalina, and now something is very wrong.


I can’t write to the HD. When the tech installed the system somehow, although I was designated as an Admin, my name is not shown on the first line of the HD ‘Get Info’ window under ’Sharing & Permissions, which would normally have designated me for both Read & Write.


Normally the new user you create when you first set up your Mac is an Admin.


‘Users & Groups’, shows that I am logged in as an Admin.


The HD ‘Get Info’ window shows ’Sharing & Permissions’ as follows:


  • system        Read & Write
  • admin          Read only
  • everyone.    Read only


So, instead of my name appearing first, with read & write privileges, all I see is the word ’system.’


When I click on the admin Read only privilege to change it to Read & Write, I get an error window which says I don’t have the necessary permission to make the change.


So essentially I’m not designated as the root admin.


Anybody know what’s going on here and how to correct it?

iMac 27″, macOS 10.15

Posted on Sep 15, 2020 5:28 AM

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User profile for user: den.thed
den.thed
User level: Level 10
82,360 points

Posted on Sep 16, 2020 7:49 AM

Yeah' Catalina is a lot different than the previous OS X and macOS versions.

Have a look at > About the read-only system volume in macOS Catalina - Apple Support

and > https://www.macworld.com/article/3451363/why-you-might-see-a-new-data-disk-in-catalina.html


Edit: also keep in mind that 10.15 Catalina is a 64Bit OS and that older 32Bit app's will no longer run in it. If this and the new file system are a problem for you, then you might want to consider running Mojave until you can find 64Bit replacements. see > https://www.stclairsoft.com/Go64/

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User profile for user: den.thed
den.thed
User level: Level 10
82,360 points

Sep 16, 2020 7:49 AM in response to -Doug

Yeah' Catalina is a lot different than the previous OS X and macOS versions.

Have a look at > About the read-only system volume in macOS Catalina - Apple Support

and > https://www.macworld.com/article/3451363/why-you-might-see-a-new-data-disk-in-catalina.html


Edit: also keep in mind that 10.15 Catalina is a 64Bit OS and that older 32Bit app's will no longer run in it. If this and the new file system are a problem for you, then you might want to consider running Mojave until you can find 64Bit replacements. see > https://www.stclairsoft.com/Go64/

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User profile for user: den.thed
den.thed
User level: Level 10
82,360 points

Sep 15, 2020 5:58 AM in response to -Doug

Sounds like the iMac was not properly prepared for sale by the original owner or by the tech.

see > What to do before you sell, give away, or trade in your Mac - Apple Support


If you can not erase and reinstall as per step #7 in the above article.

see > How to erase a disk for Mac - Apple Support


Then you need to return it to the seller and get your money back.

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User profile for user: -Doug
-Doug Author
User level: Level 1
4 points

Sep 16, 2020 7:22 AM in response to -Doug

den.thed, Thank you for your reply.


I did as you suggested. Starting up in Recovery mode, I used Disk Utility to erase the total disk. I then continued to reinstall the most current version of the OS. This time I completed the Setup Assistant myself so I think it was done accurately.


I have the same problem as described originally.


So let me go on to describe what I'm seeing. Maybe the problem is that I was expecting this very basic step, to drag & drop to the HD, has changed since my earlier days with my previous computer.


With my previous computer I had one HD disk icon on the desktop. After opening that icon, I could drag & drop anything to the HD window.


Now I am seeing icons for 'Macintosh HD' and for 'Macintosh HD - Data' and for 'Mackintosh HD - Data'.


Now before I ask you this next question, let me preface it by saying that I have set up this computer with two admins - myself and another person.


Here's my first question: Why are there two 'Macintosh HD - Data' folders? I didn't have any such thing on my previous computer. Are those, in fact, some kind of system created partitions, or are they a normal part of this new operating system - something I'm just not used to seeing?


Next, when I go to the Get Info / Sharing & Permissions section of the 'Macintosh HD', I see the same info as before the new installation:

  • system        Read & Write
  • admin         Read only
  • everyone.    Read only


And, as before, although I was set up as System Administrator, I am prevented from changing the admin privilege from 'Read only' to 'Read & Write.'


As System Admin, why would I be prevented in doing anything at all?


Any thoughts on all of this?

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HD Read & Write permissions

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