Migration Assistant says "There's Not Enough Space" on iMac

It likely will not work because you are trying to stuff a size 12 foot into a size 5 shoe. I suspect that you bought a smaller drive on the new Mac than the old Mac has. If that is the case, return the new Mac and buy yourself one with the same if not more storage than the old Mac. Then when the new machine arrives follow the steps below:

·       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: 

·       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. 

bojocq wrote:

Thanks everyone. My old iMac had a 500GB hard drive that was about 3/4 full. I had planned to port everything over to the new iMac, which, it turns out, only has a 245GB hard drive (which I found out after I canceled the migration assistant and did superficial set up on the new iMac).

Thanks for the advice on slimming down the MacOS. I've already gotten ride of big applications that are easy to re-download and transferred more files offline storage.

Bottom line, Migration Assistant works fine. I should have done more homework. I guess Apple wants everyone to pay for Cloud storage.

Migrating from a 500 GB drive that is 75% full to a 245 GB drive? Impossible, and getting rid of big applications just so you can redownload them later isn't really saving any space. There are MANY posts in the Discussions from people with 250 GB internal drives trying to figure out what to do as their disks are full. Most of the space is usually not taken with "big applications" but rather with your account's files, e.g. photos, music, documents, and emails. I think rkaufmann was correct -- you should return your Mac and replace it with a new new one that has at least 1 TB. Starting off with a new Mac that is 75% full from the get go is asking for misery. I think a new Mac should start off with no more than 25% full, thus giving you room to grow as more thing are added.

What size drive do you have in your new M4 iMac?

If you've been using Time Machine for some time you can free up a lot of space by deleting the local snapshots on the boot drive with Disk Utility:

Always leave the latest one intact.

Also uninstall any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac according to the developers' instructions. They are not needed and can interfere with normal system performance.

How much data from the old iMac are you trying to move? All your message shows is that you have 215GB of space available, but not how much more needs to be moved.

No it's not that Apple wants people to buy more iCloud storage. That is your opinion, you made a mistake by not doing your due diligence and buying the correct amount of storage for your needs. Sorry to be so blunt however that is the simplicity of it.

iCloud is simply there to sync you data across all of your devices. It is not there as extra storage, backup or anything else. It is simply a tool for syncing data.

hcsitas wrote:

It is extra storage, backup and much more:

You need to catch up with the times @rkaufmann, sorry to be so blunt 😁

rkaufmann is pretty caught up. And better to be correct than just blunt. iCloud (which I am a satisfied user of) provides backup for devices like iPhones -- it enables a complete backup of the latest state of your iPhone. But restoring is all or nothing, excellent for a migration or a disaster (complete loss of iPhone), but it's limited. But iCloud is NOT a true backup for a Mac: it provides a mirror image of SOME files on your Mac, but if you delete something on that Mac (or on a different device), the iCloud copy is also deleted (as are the copies on all the other devices). It does provide a backup for a SUBSET of your files in the event of a complete failure of loss of a Mac, as then you can restore the iCloud files to a new Mac, but not all files/folders on a Mac are duplicated in iCloud, for instance Library files are not duplicated in iCloud. So some items would not be restored. So for a Mac, it is NOT a true backup (albeit nice to have for other reasons). For an iPhone it is an all or nothing backup.

Save storage space? Yes if you choose the option to store large files ONLY in iCloud, not on your Mac. But then if you are on an airplane or somewhere where the internet is non-existent or very slow or spotty, your access to your files is impeded. So you can save storage space but at the price of sometimes not being able to access those files.

I guess consider that you are working on a massive MS-Word document, and Word crashes and corrupts the file. With a traditional backup to an external drive, you restore from the last backup before the corruption and get back to work. If your only "backup" is iCloud all your copies on all your devices and the one in iCloud are corrupted.

I use iCloud and am very happy with it. But I don't see how it can be considered a backup except for iPhone (and iPads). And it can indeed save you storage, but at a price, because there may be times when the offline stored files are not available (or may take a long time to download to gain access).

I’m not going to issue a how-to user guide on iCloud, but it serves all my needs including recovering deleted files:

As for Microsoft file recovery, see https://support.microsoft.com/en-us/office/how-do-i-turn-on-autosave-dbd19b49-ff3a-48f5-8294-671e33a6712c

Granted iCloud+ isn’t for everybody (especially those on a plane having a sudden itch to download large files 🙄)…it requires some effort reorganizing files for maximum benefit which those with old habits may find hard.

So to each his own. My point was that blanket dismissal isn’t appropriate -literally tons out there who use it exactly for what it’s sold for: files backup, additional storage and extra features.

Have a nice day!

Yes, I am very capable of reading Apple and Microsoft web pages on their products. I use Office and iCloud myself. Microsoft Office files can be unrecoverable when they get corrupted, regardless of Microsoft settings. And while iCloud does provide a single backup of one's iPhone, I don't consider the ability to recover an iCloud deleted file in the past 30 days a real "backup" system. Sorry. Not buying that story. I have seen many instances how critical having a true backup on a separate external drive is. Anyone who develops software and delivers software products understands that. That's why there is Time Machine for Macs (in addition to iCloud). I think RKaufmann already explained that to you.

What part of “Granted iCloud+ isn’t for everybody” and “to each his own” wasn’t clear? My point was that blanket dismissal isn’t appropriate - literally tons out there who use it exactly for what it’s sold for: files backup, additional storage and extra features.

Have a nice day!👋

It is extra storage, backup and much more:

[Edited by Moderator]