Aliases failing after migrating to new disk

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Level 1

26 points

Aliases failing after migrating to new disk

I migrated from my original 500GB disk to a new 1TB disk by using Disk Utility's "Restore" function. For those of you that are not familiar with Restore, it should be the highest fidelity form of coping a partition given that it does a "block copy" - e.g. it copies the data byte-by-byte instead of doing a file based copy. Also it verifies after the copy is done. In my opinion, it is the gold standard for copying an entire partition.

The new disk booted up fine, but I was surprised to find out that about half of my 190 aliases were broken. When I looked inside the alias files themselves I saw that they contain a lot of data, including a path to the target file. In all cases where the aliases stopped working on the new drive, this path was not correct. In other words, I had moved the target file on the old drive before cloning the whole partition onto a new drive.

I reinstalled the old drive and verified that all my aliases were in fact functioning so this was not an issue in on the source disk. The aliases were able to work properly even with outdated path data in them.

After doing some reading on how OS X aliases work, I found out they use multiple ways to find the target file. If the path inside the alias is not good, OS X has other means to find the original target file. But somehow this broke after copying to the new disk.

So the question is if there is a way to force aliases to get refreshed so that all their data is correct? In other words, before I do a migration to a new disk, can I run some command that causes all the aliases on my existing disk to be resolved to their targets and then have the contents of the aliases be made fully consistent with that resolved target data. This would fix the broken paths in the aliases which would allow them to work after the migration to the new disk.

MacBook Pro, OS X Mountain Lion

Posted on Jul 13, 2013 1:25 AM

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Answer 1

baltwo

Level 9

62,362 points

Jul 13, 2013 12:06 PM in response to Rumboogy22

Rumboogy22 wrote:

In my opinion, it is the gold standard for copying an entire partition.

I question that opinion. See http://help.bombich.com/kb/explore/the-block-level-copy for details. A file-level copy preserves all alias links and also results in an unfragmented copy. Just my

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Answer 2

Rumboogy22 Author

Level 1

26 points

Aug 14, 2013 12:35 PM in response to baltwo

I am not sure what your point is to link to the CCC website. But you may find it interesting to know that CCC's block level copy calls the same function as is used in Disk Utility Restore. So they are functionally the same operation, just different user interfaces.

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Answer 3

Rumboogy22 Author

Level 1

26 points

Aug 14, 2013 12:45 PM in response to Rumboogy22

So I guess no one has any good solutions to the Mac alias problem - at least no one reading this thread.

I have looked at a number of third party solutions to fix broken aliases but all they do is just find the broken alias. You can use the Finder/Spotlight to do that. I want something that will add some intelligence to fixing the broken alias and help me find the original, not just open a box for me to locate it mannually. Or better yet, something that will "refresh" the aliases (by this I mean update all the data in the alias to be correct) before I migrate to a new disk thereby eliminiating the problem all together.

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Answer 4

baltwo

Level 9

62,362 points

Aug 14, 2013 2:09 PM in response to Rumboogy22

Rumboogy22 wrote:

I am not sure what your point is to link to the CCC website. But you may find it interesting to know that CCC's block level copy calls the same function as is used in Disk Utility Restore. So they are functionally the same operation, just different user interfaces.

The point was that a file-level copy does the trick. Although it might be a bit quicker to do a block-level clone w/CCC, it reproduces the fragementation existing on the original volume. I use CCC's file-level copy function and have never had an issue with aliases. So, why don't you give that a whirl and see if your problem goes away.

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Answer 5

Rumboogy22 Author

Level 1

26 points

Aug 14, 2013 2:18 PM in response to baltwo

I have tried the file mode and it does not solve the problem. CCC will copy alias files exaclty (according to Mike Bombich). The problem seems to stem from the ID of the drive changing when you go to a new drive. This breaks the Mac's alias resolution function in the case that the target has been moved (before the copy).

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Answer 6

Csound1

Level 9

59,973 points

Aug 14, 2013 2:33 PM in response to Rumboogy22

Rumboogy22 wrote:

So I guess no one has any good solutions to the Mac alias problem - at least no one reading this thread.

This problem simply does not exist for me, aliases work after cloning with CCC (DU also). File or Block makes no difference.

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Answer 7

baltwo

Level 9

62,362 points

Aug 14, 2013 2:40 PM in response to Csound1

What Csound1 said.

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Answer 8

Rumboogy22 Author

Level 1

26 points

Aug 14, 2013 5:51 PM in response to Csound1

Try this:

Make a folder on your destop called F.

Inside folder F make two subfolders called A and B.

Inside A create a text file called T.

Now creas an alias to T which we will call T.alais.

Test out T.alias. It should open T.

Now move T to folder B.

Again, test out T.alias. It should open T even though it has been moved.

Now use CCC to copy F to another disk.

Delete the original F and empty the trash.

Now try to open T.alias. It will fail.

The reason it fails is that you moved the target of an alias (from A to B) then copied the whole thing (both alias and target) to a new disk.

I just tried it and it failed for me.

This is what happens to me en-mass when I move from one disk to another.

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Answer 9

Rumboogy22 Author

Level 1

26 points

Aug 14, 2013 5:59 PM in response to Rumboogy22

Actually, what I suggested above is not right. It should fail because it is a new path. To demonstrate the problem that I am talking about you would have to clone the entire directory with folder F in it and then boot from it. Then the absolute path to F would be the same as before yet the alais would fail.

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Answer 10

Matty725

Level 1

11 points

Sep 17, 2015 10:17 PM in response to Rumboogy22

I have this same problem. Did you ever find a resolution to this issue?

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