time machine permissions problem

Twocybers wrote:

. . .

A few items not previously covered- instead of the "Fetching" item in Sharing and Permissions, I had "wheel" this was reset as you describe in your E10 Trouble shooting piece.

. . .

after the permission reset all new backups (folders and files) behaved nicely.

Great! 🙂

I am currently over 3 hours into resetting the permissions for all the files and folders contained in my entire TM drive. I have been told by AppleCare once this is done I will be able to work with all backups without issue.

"sudo chmod -RN" . . .

You'll need to be very careful of all the current backups. The -N option removes the Access Control Lists (ACLs) that protect the backups from accidental changes. Ordinarly the Finder won't allow you to add, delete, move, or change anything in your backups (except deleting an entire backup folder), as that can easily corrupt them. Without those ACLs, there's no such protection. For best results, don't even look at your backups via the Finder now.

While I was not aware what the ACLs did, I can see their removal is what is happening. Thanks for the warning.

This brings up a question - while this command is removing ACLs on existing backups, will future backups have the ACL protections? (I am planning shortly on getting a second HDD and creating another TM backup - and if this one would be fully protected by ACLs that would be good to know.)

Been looking on the -RN command and could not find anything. The terminal window says the ACLs are being removed and my next planned step was checking into what an ACL is.

Thanks again.

Gordon

Atlanta

Twocybers wrote:

. . .

This brings up a question - while this command is removing ACLs on existing backups, will future backups have the ACL protections?

I'm not an expert on ACLs, but as far as I know, future backups made to the existing HD should have them. However, they're being removed from the Backups.backupdb folder and the one named for your Computer; I doubt those will be replaced in the future.

(I am planning shortly on getting a second HDD and creating another TM backup - and if this one would be fully protected by ACLs that would be good to know.)

Yes, a new set of backups will be normal.

Been looking on the -RN command and could not find anything. The terminal window says the ACLs are being removed and my next planned step was checking into what an ACL is.

-RN isn't the command; chmod is. -RN are options.

To see what a UNIX command does, open a new Terminal window and type man before the command. That will display what's called the "Man page" for it.

In this case, the explanation is fairly long; to get the whole thing listed, copy this into a new Terminal window:

man chmod | cat

The sudo they had you preface the command with means "super user do," meaning, perform the command with the permissions of the super user (sometimes called the "root" user), since a normal user doesn't have permission to remove those ACLs.

There's an ACL MANIPULATION OPTIONS section there with a bit of explanation. The ones on Time Machine backups basically say deny everybody everything except read. When a backup runs, or you restore a file, that process runs as root. When you restore a file, Time Machine (running as root) removes the ACL on the restored copy. These are in addition to the basic permissions you can see via the Finder See http://en.wikipedia.org/wiki/Access_control_list for an overview.

I've done a bit more research and experimentation.

Running that command does allow you to change items in the backups, but doesn't appear to let you move or delete individual files and folders.

But it will allow anyone with physical access to the backups to restore anything from them.

So your plan to start a whole new set is still very prudent. 😉

I've added a section (pink box) to #E10, detailing the instructions and downsides.

I like the addition to E10. I suggest you change or expand on the time required for the terminal command. Here is my data: Total size of Backups.backup 650MB. I have a mid 2011 iMac. FireWire 800 to WD 3.5 inch HDD with 64MB cache. The terminal was turned one, TM was left on so it was "doing" hourly backups. No other programs running. The Terminal command was entered between 5:45PM. The process ended between 9:45AM and 10:00AM the next morning.

As you discuss, it can be confusing to an inexperienced person (i.e. to me) to watch the terminal screen - but not necessarily for the reasons you wrote. Yes, the terminal screen does not show any data or activity when changing the permissions. When and only when terminal encounters a situation that prevents the command from being carried out will a line be entered in the terminal window. In my case there would be any where form 1 to as many as 50 lines of text almost instantly dumped into the terminal window. Followed by a period of no screen activity that could be a few seconds or as much as 3 or 4 minutes.

In my case I certainly had many 10s of thousands of lines went through the terminal window. Eash saying an operation was not permitted. These lines if watched seemed to repeat. I don't know how many times I saw this or that file listed. Eventually I reached the conclusion each time the file was in TM it would have to cycle through the system. Just an OS installation and a few browser cache files create more small image files (gifs, pngs and jpgs) that common users would think. After all my 139GB is over 750,000 files according to SuperDuper.

Lastly for the total neophite (me again) it is helpful to know what the final terminal screen entry will be. i.e. Name of PC followed by : and finally the name of the homefolder with the $.

With hindsite, I would suggest not only closing all programs, but also "telling" TM not to perform backups during the process -- unless of course there is a reason to do same which I don't know about.

Here is screen shot which shows a typical set of messages and the return of terminal to it normal system prompt.

Gordon

Atlanta

Forgot to mention - in my browser the "pink" section has a white background inside a text box. Also I hit Print in my browser to print out the E10 section yesterday and the other boxes (green and blue) came out with white backgrounds. I use Safari 6.x.

Gordon

Atlanta

Twocybers wrote:

. . .

TM was left on so it was "doing" hourly backups.

Ouch -- not a good idea. I'll add turning TM off to the instructions.

As you discuss, it can be confusing to an inexperienced person (i.e. to me) to watch the terminal screen - but not necessarily for the reasons you wrote. Yes, the terminal screen does not show any data or activity when changing the permissions. When and only when terminal encounters a situation that prevents the command from being carried out will a line be entered in the terminal window. In my case there would be any where form 1 to as many as 50 lines of text almost instantly dumped into the terminal window. Followed by a period of no screen activity that could be a few seconds or as much as 3 or 4 minutes.

That's entirely dependant on the circumstances. It does say "there will likely be no response on the Terminal window -- and there's no progress bar or other indication (but it's possible there might be some "operation not permitted" error messages)"

When I ran it on a small set of backups, I got about 6 such messages.

I'll try to reword it a bit to say they may be many messages.

In my case I certainly had many 10s of thousands of lines went through the terminal window. Eash saying an operation was not permitted. These lines if watched seemed to repeat. I don't know how many times I saw this or that file listed.

Yes, that may appear for each instance of a file in your backups -- the more backups there are, the more of those messages you'll see.

Lastly for the total neophite (me again) it is helpful to know what the final terminal screen entry will be. i.e. Name of PC followed by : and finally the name of the homefolder with the $.

The paragraph says "The only way you'll know it's done is when you get a new prompt, like the first sample above." I'm not sure how else to say it.

And, hopefully, not many folks will want to do this anyhow!

Twocybers wrote:

Forgot to mention - in my browser the "pink" section has a white background inside a text box. Also I hit Print in my browser to print out the E10 section yesterday and the other boxes (green and blue) came out with white backgrounds. I use Safari 6.x.

I use Safari (6.0.x) and Firefox (17.0.1), with no additions or extensions. It looks fine to me on both.

I no longer have a printer, but printing to a PDF does odd things. The site is made with iWeb, so there's not much I can do about it. 😟

For my two cents:

I've had this issue with a few different folders in attempting to restore from TM. On whim, I tried the restore as the root user I had previously enabled. It's been a while since I enabled it, but I'm pretty sure if you run

passwd root

in terminal, it should ask for your local user password (if you're an admin) and for a root password, and a confirmation. Logout at local user, login as root (other user through the GUI). First and foremost, be careful when logged in as root, the superuser account is to be respected, and for the most part won't keep you from deleting critical files, or otherwise getting yourself in trouble in so many ways.

I then navigated to the folder I wanted to recover in the Finder. In my case /Hard drive name/Users/user/Library/

and in my case the /Calendars folder. I restored from a couple different dates into a folder I had made on the root user desktop, then moved that folder the the first level of my hard drive.

I logged out and then was able to swap out the folders necessary to deal with my iCal recovery issues (I needed to go back to a previous copy of my iCal data).

Hope this helps,

-jason

Hi, I had the issue this morning where an application my wife had downloaded and was running from the Downloads folder was deleted, causing a big panic. I used TM to go back a few days and found the app, and when I tried to restore I got the permissions error. My workaround, which is impractical for other than a small number of files, was to Command-i on the backup file and it presented me with a box which had an option on the upper right to send the file via email, message or airdrop. In my case email was the best option, so I clicked it and nothing noticeable happened, but when I exited time machine indeed there was a draft email with the application as an attachment, so I just saved it as a draft and copied it to the desktop and it worked fine.

Hope this is helpful to others.

- Bill

Many thanks for the discussion on this issue. Pondini's help page was extremely useful and solved my problem (I couldn't restore a folder, I used an external drive as adviced http://pondini.org/TM/E10.html).

God bless the community! 🙂

Try duplicating it.

chgrp -R admin *

This solved it for me. Thanks.

I had the same problem. My wife and I share a machine and she was logged into Airport. I logged her off and was then able to log myself in. I did not have permission when she was logged in, but once she was logged off...problem solved.

Hello,

I beg you for help to access my Time Maschine Backup, please.

The Problem: The UID of my user account on my TM backup is 501, but on my Mac it is 502.

Reason: After mainboard replacement I migrated my user account via a dummy account from my external USB backup disk.

Attempt: Pondini's "Problems after using Migration Assistant"

Details: On step 11 of the white box, I won´t get the prompt about "already being a home folder with the same name" there. But anyway, OS X Yosemite will accept my user folder. But it still has the 502 UID.

Please, what can I?

Help very appreciated. Thank you!