Q: How to regain permissions for internal storage drive?

Any commands you use in the Terminal to make changes to the storage disk require adding "sudo" at the beginning. For example, sudo chflags -r nouchg. You will be prompted for your admin password. It will not echo back to the window. You might try this instead:

sudo chflags 0 /Volumes/*

sudo chmod a+rx /Volumes/*

killall Finder

Another procedure is:

Boot into single-user mode and at the prompt enter these commands pressing RETURN after each:

 

mount -uw /

chown root:admin /

chmod 1775 /

reboot

 

After rebooting open Terminal in the Utilities folder. Paste these commands into the Terminal application to avoid typos:

 

sudo su

 

Press RETURN. Enter your admin password when prompted.  It will not be echoed to the screen. Press RETURN again. Now paste each of the following at the prompt and press RETURN after each.

 

chown root:admin /Applications

chmod 0775 /Applications

chown root:admin /Library

chmod 1775 /Library

chown root:admin /System

chmod 0775 /System

chown root:admin /Users

chmod 0775 /Users

chmod -R -N /Applications

chown -R :admin /Applications/*

 

I suggest you first print these instructions out using a large mono-spaced font so you can read them correctly. There are spaces in the lines that may not be easily observed.

Before you go & wildly change these permissions you need to answer one simple question…

Do you plan to boot from this disk ever again?

If you ever want to boot from it do not change the permissions via sudo or any other way. OS X requires these permissions & access controls to run correctly.

It would probably help if you explained why you feel the need to edit these protected files - there may be a better way that won't ruin the ability to boot. Also be aware that typos with sudo can ruin the OS you are booted from, Terminal & sudo are not tools you use without solid backups (that are safely disconnected).

Forget about booting if you hack away at permissions like has been suggested here - it will be unbootable after you alter them.

MonOnoM wrote:

Well, they're just the old user files on my hard drive; documents, photos, Logic/Ableton projects etc., they shouldn't really be protected in the first place.

Sorry that is incorrect - otherwise someone could simply move a system disk to another device & easily read all your user files (which may contain private data). Target disk mode can mean that the disk doesn't even need to be removed! OS X tries to prevent that the best it can - permissions are it's primary system that protects user data.

MonOnoM wrote:

I had considered wiping the old drive and then dragging over the folders from the time machine backup I had before I upgraded my mac, but I'm concerned I'd just get the same problems with permissions and such.

Do not try dragging anything to other disks from Time Machine. You can ruin Time Machine backups if you go digging into them in Finder or Terminal etc. OS X has the Time Machine UI to browse & export backups - use that to get access to data. Use 'Browse Time Machine' from it's menu to restore data, then consider resetting permissions on the copy etc.

The correct way to access user files is to sign in as that user & transfer files to other users via the Public/Dropbox in each home folder. Only consider changing permissions on home folders if you never want to login as that user again.

I don't have a simple answer beyond this…

Open Migration Assistant, select the option to migrate users from another disk. Migrate your old account to the Mac. Assuming you have unique user names you will have the old user on your disk once it completes. Sign in to the old user & move files to the other user via the Public/Dropbox in each home folder.

I'll leave it to others to give you Terminal commands that can edit the permissions.

I'm having a tough time working out what your overall aim is - it seemed like it was to access a few files now it seems like you'd like full access to the user data. Clarifying this would help devise an appropriate plan. I suspect I may have confused the issue too

You can migrate the data if you have the space for it. Migration Assistant copies all the user data & resets the permissions to use the new user ID.

NOTE: OS X is also happy to store a users home folder on another disk - provided that disk is always available. To do this just make a new user account (using the same 'short name' as the old home folder). Then use the advanced preferences to point the home folder to the old account on the other disk. The advanced preferences are shown when right clicking the username in System Preferences.

You may need to get OS X to fix the user permissions after that. This method should do that correctly…

http://osxdaily.com/2011/11/15/repair-user-permissions-in-mac-os-x-lion/

Ask before you make changes via this method it can be tricky to get right, but it is the correct way to move a home filer to another disk. Here is an explanation of that.

http://chris.pirillo.com/2008/02/06/how-to-move-the-home-folder-in-os-x-and-why/

Obviously that ruins permissions & the ability to login as the user on the old OS.

Considering you have already damaged the old user account permissions you can probably continue with the modifications that edit the permissions via sudo if you only want to access a few files. 

I don't know what you overall aim is but permissions are not something that you can normally just 'get rid of' at least not if you want to preserve booting or user logins.

I'm also not sure how you can just transfer files to another drive - most decent copy (one that verify a copy actually happened) apps will preserve permissions. Copying in Finder won't strip out ACL's or nested permissions either. If you have a plan, stick to it, just verify th etools you plan on using actually remove the permissions - OS X will write permissions to external disks too. Using the 'Ignore ownership' checkbox doesn't remove the permissions on volumes, it just ignores the ownership rules.

It's complex because it is how OS X is designed to work.

MonOnoM wrote:

 

I had thought I could simply use my old hard drive "as is" as a storage drive, keeping all of the files and projects that were stored on that drive, and symlinking some of my new drive's home folders (photos, music, movies, etc.) to point to the folders on the old drive, and copying over a few important preferences and plugin components to my new drive.

This is all achievable.

Personally I find symlinks are fragile, ideally if you can use the same home folder on 2 OS's that makes it simpler. It requires a little care & setup but it is possible to use one home folder for multiple OS's, ideally the OS is the same version but it isn't totally critical.

That does mean that you have one home folder without the possibility of customising things.

You can also save files to the 'base' of a system drive, however you will have to create a folder as admin & then loosen the permissions to allow other users to access that folder. The OS likes to protect that location, so it is is best to use the home folder for your own data or use /Users/Shared/ for content everyone needs to access. It's up to you if you'd rather save to the base of the disk, it is not impossible, just not recommended & a little non-standard nowadays.

Overall I'd say you can achieve what you desire without having to break the old OS's permissions.

The first step would be to confirm the state of the old OS… boot the old OS & check the old user logs in & functions. Repair the disk permissions in Disk Utility. NOTE: will not fix user permissions. Use recovery mode to repair disk permissions if it won't boot & retry.

If that works fine you can add a new user to the second OS & then point the new users home folder to the old location. You will also need to set the same UID (user id) as the old one, this is also done in the advanced section of the preferences.  I'm trying to keep the explanation short, so ask if you want more detail.

Your general aims seem achievable to me, it really depends on if you can limit yourself to one home folder, or only want to symlink pieces to the old one. Symlinks can fail & I have had issues with them, so I don't recommend them for critical data like the home folder because some apps can misbehave if you have files in unexpected paths.

The ARD error in Disk Utility is normal, don't worry about that…

Mac OS X: Disk Utility's Repair Disk Permissions messages that you can safely ignore - Apple Support

To set the OS to use the one home folder shared to multiple OS's the process is as follows. Please read all before you begin, there are some considerations at the end.

I'm labelling each OS to try to make it clear '[source]' is where the home folder exists '[dest]' is the OS that will gain access to the new account.

Ensure you have an admin account on both OS's - this needs to be different to the user account you plan to change.

STAGE 1 On the [source] OS.

Ensure the account you plan to share can login & works OK.

1. Login as your admin
2. Open 'System Preferences > Users & Groups', unlock the panel if it is locked (admin access is needed).
3. Select the user you plan to share, ctrl+click on the username (or right click), select the 'Advanced Options…'
4. Make a note of the 'User ID' and 'Account name'. You will need to access this on the other OS later, so write these down.
5. Close the advanced options & reboot into the [dest] OS.

STAGE 2 On the [dest] OS.

1. Open 'System Preferences > Users & Groups', unlock the panel if it is locked (admin access is needed).
2. Confirm that ALL of the other users on the system are not using the same User ID - use the advanced options to check each user account manually, but do not change any settings.
3. If there is an existing user with the same User ID STOP NOW & post back, otherwise continue…
4. Create a new user - use the same name as the account name on the [source] OS, it is best use the same password too so the keychain will be unlocked in both OS's.
5. Once created you can edit the new account under the advanced options.
6. Set the user ID to the same as the user on [source].
7. Set the home directory to '/Volumes/{name of source disk}/Users/{account-name} to the same as the user on [source] (insert the name of your disk & the user account)
8. Save the changes.
9. Try logging in as the user you created, (change the desktop background as a test).
10. Reboot to the other OS & login see if your desktop is the same.

Note any errors & post them here.

You previously asked about switching into this account. That is up to you just be sure to keep a functioning admin on both OS's otherwise it can be difficult to fix any errors. Merging user accounts is always difficult when you consider preferences & other files that do not merge well, you may find it simplest to copy over any files you need but permissions will still be an issue. They will need repairing after you copy them to the new account.

OS X has two types of 'repair permissions feature' - one is built into Disk Utility & it repairs the permissions of installed apps (only apps that used installers). The other method is built into recovery mode. You use a tool called 'resetpassword' in recovery mode, opened from Terminal. It is opened as explained here…

How to reset the user password in OS X Lion and newer OS X releases

There are options in that tool to reset user permissions despite it's name, you simply select the user account & apply the reset password.

P.S. Apologies for the delay, I was away from my Mac & needed to clarify a few things.

Post back if anything is unclear.

As always this is fairly a major change, so make a backup beforehand of any important data.

You shouldn't need to edit any admin accounts. You just need to have a functioning admin on each OS disk. Only create a new admin if you only have one account on the source system. You need to avoid trying to modify the only admin user on either system.

You can revoke admin access if you desire - it really doesn't matter provided the admin accounts have passwords and you keep one admin user on each system.

You are not changing anything in /System or the other places you mention. You are simply creating new account and then telling OS X to use a home folder on the other disk. The only consideration is that the user ID needs to match on each OS installation, otherwise permissions can get in a mess.

The passwords can be different on each account, there is one nuance that is easy to miss – the login keychain. That is normally unlocked with your login password. If the keychain password is not the same as the login password you have to unlock it manually. It is not a problem, just something that confuses most users who do not realise that the password is setup in 2 places not just one. Obviously you can't have 2 different login passwords that match the single keychain password (you have one home folder with this setup).

If this is too confusing try detailing your setup so it is clear what users are on which OS disk & what User ID's they have & their admin status.

We can determine all of that info via Terminal commands but I was hoping to avoid a lot of back & forth since I don't know how often I can reply.

If this is all too confusing it is best to avoid doing this - it is non standard & may lead you to get into a mess, but you seem convinced that you want to login from multiple OS's.

I think the audio plugins should work if you place them into the correct folder - ideally it is better re-run the installer that created them in the first place, otherwise permissions can be incorrect.

Installers create a 'bill of materials' that is used to repair these permissions. You won't have that BOM file without running the installer.

The keychain will bug you when the login password is different. It doesn't really matter if you can unlock it when prompted.

I'm glad it seems to have worked out for you

Re-read the part I posted about 'resetpassword' it can be used to fix user permissions from recovery mode, but it seems like you have them correct so far.