JDW1

Q: How to change permissions on external FW800 Time Machine backup drive.

I started a related discussion here, but replies dried up for reasons unknown, hence my zeal to start this new thread.  Hopefully this new topic will garner the attention it deserves.

 

As I stated in that other discussion, I have an external FW800 hard disk that I used with my old 2009 iMac (running El Capitan) to make Time Machine backups.  I recently purchased a 5K iMac and am trying to continue using it without reformatting it, so as to retain the older backups I have on it.  But when I use ENTER TIME MACHINE, I find I cannot go back in time to see older backups, even though I can see them by digging down into the drive in the Finder.  I believe the problem pertains to the fact that I see many folders with the round, red bar icon (which means "no access").  My computer name has changed, but my login name and password is the same on this new iMac.  Even so, I am barred from accessing many folders.

 

How do I change permissions on my external drive so I have full access to every file and folder on it?

 

Thank you.

Posted on Nov 26, 2015 5:14 PM

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Q: How to change permissions on external FW800 Time Machine backup drive.

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  • by Nubz N.,

    Nubz N. Nubz N. Nov 28, 2015 5:29 AM in response to JDW1
    Community Hosts
    Nov 28, 2015 5:29 AM in response to JDW1

    Hi JDW1,

     

    It sounds like you would like to access the files on the external hard drive that are backups from your earlier iMac but you are locked out by permissions. Of course Time Machine on the new iMac won't access them as they are backup of a different computer.

     

    Did you migrate the data into the new iMac so you could then back them up with the new iMac?

    Move your content to a new Mac - Apple Support

    Connect the computers to each other

    But to focus on your current question, does "Ignore ownership on this volume" work for you?

    OS X El Capitan: If you don’t have permission to use files on a disk

    If you don’t have permission to use the files on a disk that’s connected to your Mac and you are not the administrator of the Mac, ask the administrator to give you access to the disk. 

    If you are the administrator you can select an option to ignore ownership of those files. When this option is selected, your Mac treats all files on the disk as though they are owned by the current user, no matter who actually owns them. 

    1. Select the disk, then choose File > Get Info.

    2. Click the disclosure triangle next to Sharing & Permissions to expand that section.

    3. If necessary, click the lock icon , then enter an administrator name and password. 

    4. Select the “Ignore ownership on this volume” checkbox.

    Take care.

  • by JDW1,

    JDW1 JDW1 Nov 29, 2015 4:47 PM in response to Nubz N.
    Level 1 (18 points)
    Mac OS X
    Nov 29, 2015 4:47 PM in response to Nubz N.

    Thank you for your reply, Nubz.  But sadly, there is no "Ignore ownership on this volume" setting on my 5K iMac running El Capitan.  Here's what I am doing:

     

    1) Click once on the FW800 drive icon sitting on my Desktop to select it.

    2) Get Info

    3) Open "Sharing & Permissions" at bottom.

    4) Click the LOCK icon and enter PSW to unlock it.

    5) I then see the following:

    • system = Read & Write
    • admin = Read & Write
    • everyone = Read & Write

    6) Clicking on "Read & Write" for "system" and "admin" shows these 3 choices:

    • Read & Write
    • Read only
    • Write only (Dropbox)
    • ("everyone" adds an "access" setting too the above 3)

     

    I don't see "Ignore ownership" anywhere.  And again, I am clicking on the desktop icon of the drive itself, not a folder inside it.

     

    Here's a screenshot of the bottom of my Get Info box:

     

    https://www.dropbox.com/s/59651x2z9h0fgtj/IgnoreOwnershipMISSING.png

     

    Perhaps someone will come along and say, "that 'Ignore Ownership' setting doesn't exist on Time Machine backup drives."  My reply to that would be, "Okay, can I accomplish it via a Terminal hack?"

     

    I'm desperate at this point.  And NO, I refuse to erase the drive and start over.

     

    Please advise.

  • by JDW1,

    JDW1 JDW1 Dec 1, 2015 12:19 AM in response to JDW1
    Level 1 (18 points)
    Mac OS X
    Dec 1, 2015 12:19 AM in response to JDW1

    Pretty please?

  • by JDW1,

    JDW1 JDW1 Dec 1, 2015 12:59 AM in response to JDW1
    Level 1 (18 points)
    Mac OS X
    Dec 1, 2015 12:59 AM in response to JDW1

    I've been reading about Terminal commands that could possibly solve my permissions problem on my external TM HDD, but I need the advice of you experts as to which of the following 4 lines is correct (noting that my external FW800 TM HDD is named "2TB Backup"):

     

    CHANGE OWNERSHIP

     

    sudo chown -R `id -un` ~/Volumes/2TB\ Backup


    sudo chown -R `id -un` /Volumes/2TB\ Backup


    sudo chown -R `id -un`:`id -gn` ~/Volumes/2TB\ Backup


    sudo chown -R `id -un`:`id -gn` /Volumes/2TB\ Backup



    And I assume the following is correct because I found it on this pondini.prg webpage on archive.org, but it would appear to carry much more risk than a mere Change of Ownership:


    REMOVE ALL ACCESS CONTROLS


    sudo chmod -RN /Volumes/2TB\ Backup



    I look forward to your helpful replies.

  • by Nubz N.,

    Nubz N. Nubz N. Dec 1, 2015 7:03 AM in response to JDW1
    Community Hosts
    Dec 1, 2015 7:03 AM in response to JDW1

    Howdy JDW1,

     

    It looks like the option to ignore ownership may be because it's a Time Machine backup drive.

    From iPhoto: Sharing libraries among multiple users - Apple Support

    Important: If you've selected this volume for use as a Time Machine backup, you will not be able to select the option to ignore permissions on the same volume.

    So due to the nature of your issue or question you may find more information by using another one of Apple's support resources - https://getsupport.apple.com/GetproductgroupList.action

     

    Take care.

  • by JDW1,Solvedanswer

    JDW1 JDW1 Dec 7, 2015 4:13 PM in response to Nubz N.
    Level 1 (18 points)
    Mac OS X
    Dec 7, 2015 4:13 PM in response to Nubz N.

    Thank you for your suggestion and for your 2 kind replies here, but please understand I prefer NOT to pay for Apple Support (what you referred me to), which is why I posted here in the Support Communities.


    I have found the solution myself, and for the sake of others who find this thread, following in my footsteps, I will share all the steps I took to discover that solution, as follows...

     

    It seems that the tilde "~" character means "home directory" in UNIX, which is clearly something I do NOT want to use, so I ran the following line in the Terminal:

     

    sudo chown -R `id -un`:`id -gn` /Volumes/2TB\ Backup


    I let it run about 15 minutes and many files on my TM backup drive scrolled across the screen.  But after each line it said, "Operation not permitted."  So a change of Ownership via the Terminal on an external TM Backup drive does NOT work.  I used CNTRL-C to cancel. 


    I then used the following Terminal command to check the permissions on that drive:

     

    ls -led /Volumes/2TB\ Backup


    Terminal replied:


    drwxrwxrwt  8 root  admin  680 Nov 30 15:55 /Volumes/2TB Backup


    I then opened the 2TB Backup drive and checked inside my User folders.  But the red circle with bar which prevents access remains visible.


    — — — — — — — — — —


    I then tried Pondini's TM support page suggestion (which he says is a "last resort") in the Terminal to remove all access controls:


    sudo chmod -RN /Volumes/2TB\ Backup

     

    After a few seconds, Terminal replied:

     

    chmod: Failed to clear ACL on file Desktop PN: Operation not permitted

     

    Terminal then sat there, with a gray block text cursor sitting beneath the above line, rather than give me the normal "[MacName:~ HomeFolder$" prompt.  But after about 5 minutes, Terminal replied:

     

    chmod: Failed to clear ACL on file coreservicesd_3216FE5A-C240-5B0B-BBBF-A771A3B135CA_CrashHistory.plist: Operation not permitted

    chmod: Failed to clear ACL on file mdworker_3216FE5A-C240-5B0B-BBBF-A771A3B135CA_CrashHistory.plist: Operation not permitted

     

    So I just left the Terminal to finish the job until I could see the regular prompt.  Terminal continued to report certain files in the same manner ("chmod: Failed to clear ACL on file... Operation not permitted").  I let it run for a couple days, but then grew weary of it so I cancelled within the Terminal.  When I checked my FW800 drive in the Finder, the red circle and bar preventing access was still there.  And using Enter Time Machine still does not allow me to go back in Time to access old Backups on that drive.

     

    — — — — — — — — — —


    I then fired up my old G4 Cube running OS 10.4, with my fingers crossed.  Why?  Because Time Machine was introduced in Leopard, and I have Tiger (one OS X version prior) on my G4 Cube.  It was my hope that I might get lucky with permissions tweaks.  To my delight, OS X Tiger allowed me to use the Finder Get Info box to change permissions on my external FW800 TM drive to Read/Write, even for "Everyone," although it was only on folders I selected inside my User folder of each backup.  It took me a few hours of manual labor to tweak permissions that way, but I persevered and accomplished the task. 


    I had tried to use Terminal commands on my G4 Cube and let it run over a weekend, but permissions were NOT changed.  Not sure if it is a bug in Tiger or just Tiger's lack of knowledge about Time Machine, but I was able to exploit it to my advantage insofar as the Finder Get Info box works under Tiger.  Once again, I manually opened my "user" folder inside each backup, selected all the folders inside, then used Get Info to change the permissions to READ/WRITE for system, wheel, everyone (all listed).  I then moved that FW800 drive back to my iMac and checked.  I can now use the ENTER TIME MACHINE command, I can restore files just fine (going back several years), AND I can continue making Time Machine backups too.  HURRAH!  PROBLEM SOLVED.


    So for those of you following in my footsteps, using an old Mac running OS 10.4 (or possibly earlier) is the old fix I could find.


    I must admit that it's sad I even need to go through this though.  These are MY files.  I should NEVER, EVER be barred access from them, regardless of whether I change to a new Mac or not.  It's not right.  And no, I shouldn't be forced to erase my TM HDD and start over either.  That should be MY CHOICE.  Thankfully I found a solution.  I can access old backups AND continue making new backups with my new iMac to my external FW800 HDD.  I am greatly relieved.