Can I use the same user accounts for both Lion & SL?

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Level 1

16 points

Can I use the same user accounts for both Lion & SL?

I have one Mac that I can upgrade to Lion but it is the one that the entire family uses every day (I only can use it (and administer it) on weekends), so I have to make sure that there are no problems and no issues so my plan is to:

Move all of the users accounts to a different drive.
Configure 10.6.8 (SL) to use the user accounts on the different drive.
Back up SL to a bootable drive.
Repartition the Mac for a SL & Lion partition.
Reconstitute SL on both partitions.
Upgrade one SL partition to Lion.

I should now have a partition for SL and Lion that both use the same users accounts so when I (and then my family) are comfortable with Lion, the switch will be transparent.

Any problems that I am unaware of (and how to remediate it)?

TIA.

Posted on Jul 28, 2011 7:52 PM

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Answer 1

Jul 28, 2011 10:30 PM in response to barubin

That approach may work with "plain" documents, but won't work for files that belong to applications like Mail, Safari, or Address Book. The files that go with the newer versions of those applications aren't compatible with the older versions.

How do you plan to "move all of the users accounts to a different drive"? Copying those files with the Finder won't necessarily work well.

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Answer 2

barubin Author

Level 1

16 points

Jul 29, 2011 8:34 AM in response to William-Boyd-Jr

There are a few discussions here on the topic that I was planning to employ:

Moving Home folder to different HDD From Mac OSX Snow Leopard via Terminal?

Moving some Users to different volume

How do you move a user account to a different drive?

Another way of doing it is to move the directory, and then alter the user's home directory using the NetInfo utility (Tiger) or Directory Utility (Leopard). In both, you can change the user's home directory from the command line in Terminal.app like so:

$ sudo dscl . -create /Users/user NFSHomeDirectory /Volumes/volname+/+user

In the SL System Preferences -> Accounts one can select a user's account, right click and choose Advance Options presents the screen below. This is how I intend to point each OS to the same user account on an external HDD.

Does that answer your question?

TIA.

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Answer 3

Jul 29, 2011 8:37 AM in response to barubin

It sounds like you've found some good advice about how to move user folders. However, there's still the issue of incompatibiity of data for the applications that I mentioned (and others) across versions.

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Answer 4

barubin Author

Level 1

16 points

Jul 29, 2011 8:45 AM in response to William-Boyd-Jr

William Boyd, Jr. wrote:

However, there's still the issue of incompatibiity of data for the applications that I mentioned (and others) across versions.

Well, that's why I asked the question. Nobody uses Mail, I'm the only one that uses Address Book, and the others use Firefox, not Safari. I know how to tell which applications won't work with Lion because of the lack of Rosetta. How can I determine which applications have new/incompatible file formats?

TIA.

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Answer 5

Jul 29, 2011 8:56 AM in response to barubin

I would presume that any Apple application that has user data has changed its format for Lion. It sounds like Address Book and Safari are the two that will affect you the most.

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Answer 6

barubin Author

Level 1

16 points

Jul 29, 2011 9:06 AM in response to William-Boyd-Jr

William Boyd, Jr. wrote:

I would presume that any Apple application that has user data has changed its format for Lion.

What has changed in Lion that you "presume that any Apple application that has user data has changed its format for Lion"?

I haven't read anything in the public domain, yet, that would indicate such an issue.

TIA.

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Answer 7

Jul 29, 2011 12:55 PM in response to barubin

barubin wrote:

What has changed in Lion that you "presume that any Apple application that has user data has changed its format for Lion"?

How about all the software version numbers?

- Safari 5.0.x vs. 5.1 (although this won't be as big a problem with the release of Safari 5.1 for Snow Leopard)

- Mail 4.5 vs. 5.1

- iCal 4.0.4 vs. 5.0

I haven't read anything in the public domain, yet, that would indicate such an issue.

You won't see anything, mainly because each of these applications performs any necessary conversion of user data the first time it's launched, and few people want to do what you want to, which is to use the same user directory for Snow Leopard and Lion. That's the real trick.

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