Migration help with Late 2009 iMac HiSierra to new M4 Mac mini with attached 2TB Express thunderbolt drive

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Level 1

32 points

Migration help with Late 2009 iMac HiSierra to new M4 Mac mini with attached 2TB Express thunderbolt drive

My goal is to migrate from my legacy iMac to the new M4 Mac mini by keeping the system on the Mac mini (16/256) and all else on the OWC Express 1 M 2 2TB External SSD drive. I am obviously strapped financially (fixed income) so I try to keep the purchases reasonable. I have keyboards and mice for each, but I don’t really grasp the best method (connectors and cables) for the migration. I do possess an old OWC Mercury Elite-AL Pro Dual-Bay which has FireWire 800, FireWire 400 and USB 2.0 ports. My iMac has close to 500GB on the internal drive and the new Mac M4 mini has the smallest 256GB drive. I have been recommended to purchase a 1TB external drive and use TimeMachine to back the iMac on it then migrate from that drive to the M4 Mac mini. Yup I should not have waited so long to do this, but here I am and asking for guidance or best solutions if you can help. Much appreciated…

Earlier Mac models

Posted on Dec 28, 2024 05:27 AM

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Answer 1

rkaufmann87

Level 10

148,080 points

Dec 28, 2024 10:14 PM in response to J Langlois

· Always connect your old Mac's Time Machine External Hard Disk prior to startup, this will allow a migration from your TM backup and it will be dead simple! When you start the new Mac for the first time it will startup Setup Assistant (SA), SA will get to a point where it asks if you are migrating from another computer, select Yes and follow the on-screen prompts and it's done! It is that simple! This is the easiest, quickest and most reliable method to migrate from the old Mac to the new Mac is to simply connect the old Mac's Time Machine External Hard Disk to the new Mac using a USB cable before you turn on the new Mac.

· NOTE 1: You will likely need a USB A to USB C adapter, you can find them on Amazon for $10 or less. Something like: USB to USB C adapter

· NOTE 2: If you have already done SA on the new computer then simply connect the Time Machine External Hard Disk using a USB cable and launch Migration Assistant (MA) which is located in Applications - Utilities - MA. Then follow the on-screen prompts.

· The ONLY difference between MA and SA is MA will create a new user account that you need to log into.

Both SA and MA migrate applications (not 32 bit apps), data files & settings. They do not migrate Mac OS itself. Some professional apps such as Adobe and Microsoft apps may require re-installing their apps as they will not allow them to be migrated. As long as you kept the security keys for installing their apps, it is not an issue.

Finally, my recommendation is not using Wi-Fi when doing Setup Assistant or Migration Assistant. Why, it simply fails in a lot of the cases reported in these forums. A wired connection is more reliable and the last thing you need is a failed migration when there are safe methods readily available. Please read and follow the directions in Setup Assistant and Migration Assistant. If you do not have a Time Machine backup of the older Mac then create one!If you are not aware of Time Machine, please read Back up your Mac with Time Machine and finally if you need an External Hard Disk to use as a Time Machine External Hard Disk then many experience users on these forums prefer the OWC Mercury Elite Pro due to it's reasonable price, high level of quality and ease of use.

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Answer 2

BDAqua

Level 10

250,103 points

Dec 28, 2024 11:47 AM in response to J Langlois

I think I'd try installing your newest OS to the external 2 TB drive, Migrate to that, then figure out what you want on the Internal drive.

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Answer 3

J Langlois Author

Level 1

32 points

Dec 29, 2024 03:17 AM in response to BDAqua

I like that approach, thank you. I am reading though, the Apple tech support, if needed won’t support that strategy. I also read that you will not be able to play with or work with Apple’s AI either as it doesn’t like working on an attached drive. Have you any suggestions or experience on those two caveats? Thanks so much. I have been out of the “loop” for many years and now grappling with some new challenges that didn’t exist twenty or so years ago!

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Answer 4

J Langlois Author

Level 1

32 points

Dec 29, 2024 03:30 AM in response to rkaufmann87

Thank you so much for taking your time to help me on this project. I’m trying to stay within the graces of Apple tech support while having the less expensive 2TB drive as my working space. I don’t know if I can pull this off and satisfy both ideas. I’ll take my Mercury Elite apart and see if I can back up to it from my 2009 iMac first. I had it set up as a RAID drive so long ago, I don’t remember what is on it. I’ll format the 1TB SATA drive and see if it’ll do what I need. Thanks for the advice on the USB adapter, I’ll need that in the short run for now so I won’t have to purchase more hardware that I won’t be using anymore. I have a challenge ahead and I gotta move slowly until I get back up to speed. 73 now and out of the tech loop for so long is giving me a real challenge. Thanks so much for your help, it is much appreciated.

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Answer 5

J Langlois Author

Level 1

32 points

Jan 1, 2025 07:58 AM in response to rkaufmann87

OK, I need help with a couple of issues if you don’t mind. My old Mercury Elite Pro has two bays and I have used it as RAID backup at some point. One drive is a 1TB eSATA drive and the other is a 160 GB drive and shows up with this description: GUID_partition_scheme EFI ( must be the format.) I can set it to run both drives independent, JBOD (span), or RAID 0 (stripe). What format should I use? I can say that the 2009 iMac has 319.8GB used on its 1TB drive, so I’d guess that backing up to the 1TB drive would suffice. I can then use the adapter you suggested to then migrate from the Mercury drive to the new. ac Mini. Since I’m using High Sierra the disk utility won’t mount the drive, but I was able to use diskutil to mount it and list what I needed to know. I just gotta figure out how to use the command line to format them once I know what format to use. What do you think? Am I missing anything? Thanks so much.

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