Mail cannot save information about your mailboxes because there isn't enough space in your home folder

FYI: For reference, if the link dies for some reason, point 3 was:

Try to reset Mail settings. - which you will need to set up after following:

Quit Mail, then go to Finder and press ⇧⌘G and enter (or copy) the following:

~/Library/Containers/com.apple.mail/Data/Library/Preferences

Look for "com.apple.mail.plist" and drag it the Desktop, then restart Mail.

Hi All,

I was struggling with the same issue, and have been looking all over google/forums for the resolution.

I've signed up to help as it looks like (touch wood) I've finally found something that has worked and wanted to share.

Firstly, I went to System Preferences>Internet Accounts and disabled all Mail on the several accounts I have stored (I'm not sure if this assisted in any way).

I then followed step 3 from the following post:

https://apple.stackexchange.com/questions/138537/how-can-i-delete-my-mail-app-and-re-install-it

Once I had booted my Mail back up, I enabled all my mail accounts.

Let me know if this helps! My mail seems to be behaving itself since I followed these steps.

Cheers,

Charlie

OK, so I figured it might be good to search for issues relating to Catalina and Fusion drives.

I found this and I'm guessing that, if you are willing to go through a full reinstall including resetting your Fusion drive, the fix described here would work: https://discussions.apple.com/thread/250738908?page=1

Specifically these instructions:

Alright, these steps fixed my problems:

1. Create bootable USB with macOS 10.15.1 (or latest)
2. Restart Mac and press with Cmd + Option + R to start recovery mode
3. In recovery mode open Terminal and enter "diskutil resetfusion"
4. Install macOS

I did a clean install before without fixing the fusion table and several apps kept complaining about disk space.

I use an iMac 2019 with FD (using 2 SSDs, I replaced the HDD).

I haven't tried this yet.

As suggested (NikkolaPD Nov 12) here are more details of my iMac installationin

My iMac is 

iMac (27 inch, Late 2013)

MacOS Catalina 10.15.1 

Processor 3,5 GHz Quad-Core Intel Core i7

Memory 8 GB 1600 MHz DDR 

Startup disk Fusion disk consisting of 480GB SSD, 120GB Flash.    APFS formatted.

The original Fusion disk (rotating + flash) was substituted for SSD+Flash fusion by Humac Danmark (Apple Danmark) a couple of years ago.  

It was running High Sierra up to a couple of weeks ago. I had to clean install Catalina in order to upgrade.  

Catalina 10.15.1 was clean installed on the fusion disk via a bootable USB stick.

(Bootable USB stick created, Boot from USB stick, Erase and reformat with APFS the Macintosh HD volume, rebuild as Fusion volume, Migration assistant to restore sw from a Time machine backup). (see https://discussions.apple.com/thread/8551587 )

I tried the fix posted by clivesey 10th Oct 2019 1:03AM but still have the same mail problem. I have also tried clearing out all my mails in all my accounts (iCloud mail; gmail, hotmail) and applying the fix again. Still same problem. I have lots of space on my mac ( 64GB available of a 600GB SSD/flash 'fusion' drive) and am using iCloud storage where I also have tons of available space (1,8TB available!). Hope there comes a Catalina fix soon addressing this problem.

• I have looked at this and it says "If you see a drive labeled Fusion Drive, your Fusion Drive is working and this article doesn't apply to you."
• As you can see from the image everything seems to be correct, so not sure what can be done, as I have said before I am ****** if I am going to spend a day or more jumping through hoops to fix a problem that may not work; this is on Apple to sort out.

Oh, and PS. I just posted something on Apple Support Twitter.

[Edited by Moderator]

I have the same issue. Have spent approx 3-4hrs on a number of calls with Apple support and still can't fix.

For info I have done the following:

• I have done a formatted my hard drive, done a complete reinstall from backup of Catalina - didn't work
• I have formatted my hard drive and done a clean install of Catalina and then used time machine migration assistant to bring files across - didn't work
• I have formatted my hard drive and done a completed clean install of Catalina and then manually transferred files - still isn't working.

I have approx 650GB of a 1.08TB drive free

No not from my experience.

I essentially followed those steps but my iMac still has the problem! Details below: 

Perhaps the issue also is related to how the fusion drive partitions are formatted. 

I formatted the two partitions as APFS encrypted. 

i.e. My experience was:

Booted from the Catalina OS stick and erased the "Macintosh HD" volume from the Disk Utility that was available on the install medium.  

First erase failed and resulted in two partitions 

1. 
   
2. 
   
3. 
   
4. disk0s2 121,12GB
   1. 1. 
         
5. 
   
   1. 1. disk1s2 479,89GB
6. 
   
7. 
   
8. 
   

Then I performed the following using the disk utility

disk0s2 erased and created a new volume Mac120GB   APFS encrypted  (with my chosen encryption pw)

disk1s2 erased and created a new volume MacOS480GB  APFS encrypted (with the same chosen encryption pw)

I did clean installation of MacOS Catalina to MacOS480GB.

Problem was that now my 'Fusion' drive was now split. It consisted of an SSD (with MacOS installed) and a Flash drive i.e. two separate drives. 

At this point I discovered the “diskutil resetfusion” possibility… 

So I followed the steps suggested i.e.

1. 
   
2. Create bootable USB with macOS 10.15.1 (or latest)  (…already done in my first attempt)
3. 
   
4. 
   
5. Restart Mac and press with Cmd + Option + R to start recovery mode
6. 
   
7. 
   
8. In recovery mode open Terminal and enter "diskutil resetfusion"
9. 
   
10. 
    
11. Install macOS
12. 
    

Then used the migration assistant to restore my software and data from my Time Machine backup.

>> the migration assistant is in the utilities folder of the applicaton folder

>> choose migration from a time machine backup

And now I have the issue! 

Yes - I did the same. And my Mac has been stable for 2 days so far. Thanks

i.e. I did

• Bootable USB with MacOS10.15.1
• Restart Mac and press cmd + option + R to start recovery mode
• In recovery mode open Terminal (top menu, Utilities, Terminal) and enter "diskutil resetfusion"
• Install MacOS
• >>> Did NOT use migration tool
• Reinstalled my sw from scratch ... Took lots of time.. but finally got there. And now stable.

Just to recap the current understanding of the cause of this issue and how to fix it.

• It is not a mail problem. It is a problem with a corrupt APFS drive, almost always a Fusion drive
• The problem can be triggered by upgrading to Catalina, or by using Migration Assistant
• The only stable solution at the moment is to reset the Fusion drive, reformat and completely reinstall Catalina, manually migrating your old data (not using Migration Assistant), see the instructions elsewhere on this post that include “diskutil resetfusion”
• So far, no return of the errors (16 days)

Just a reminder / summary to all with this problem:

• It is not a mail problem. It is an issue with a corrupt Fusion drive / APFS volume and therefore can impact any app.
• The problem is apparently caused by the data migration process that happens during the Catalina upgrade, and can apparently also be triggered by running Migration Assistant.
• Doing a complete Catalina fresh installation including resetting the Fusion drive (and avoiding running Migration Assistant) has apparently completely resolved the issue for everyone who was tried it, myself included.

Specifically these instructions:

Alright, these steps fixed my problems:

1. Create bootable USB with macOS 10.15.1 (or latest)
2. Restart Mac and press with Cmd + Option + R to start recovery mode
3. In recovery mode open Terminal and enter "diskutil resetfusion"
4. Install macOS

Fair enough.

Interesting that two different approaches have fixed the problem. i.e.

• Split into two drives and not used as fusion any more (yours)
• Reset to original Apple fusion drive as one drive with caching (Re5i5tor)

the possible consequence of yours is that is the SSD part is small, and this eill affect Mail, the ~/Library may be fixed into the SSD and as all iphone backups are usually stored there it can quickly fill up.

My periodic refresher to all with this problem:

• The response marked "Solution" is not the solution. Unfortunately it appears impossible for anyone to unmark it.
• It is not a mail problem. You can't fix it by any fiddling with mail folders or settings. It is an issue with a corrupt Fusion drive / APFS volume and therefore can impact any app.
• The problem is apparently caused by the data migration process that happens during the Catalina upgrade, and can apparently also be triggered by running Migration Assistant.
• Doing a complete Catalina fresh installation including resetting the Fusion drive (and avoiding running Migration Assistant) has apparently completely resolved the issue for everyone who was tried it, myself included.
• Breaking your Fusion drive, which leaves you with a very small OS drive, does not appear to be a good idea.

Specifically these instructions have worked for everyone who has tried them, to the best of my knowledge:

Alright, these steps fixed my problems:

1. Create bootable USB with macOS 10.15.1 (or latest)
2. Restart Mac and press with Cmd + Option + R to start recovery mode
3. In recovery mode open Terminal and enter "diskutil resetfusion"
4. Install macOS

Cheers!

18 GB is critically low space. Do not attempt to use that machine for anything until you delete some files. You need at least 30 GB of free space to do anything. The operating system will almost never tell you how much “free” space you have. It is reporting “available” space, which is completely different. The idea is that it will “free up” space if you run low. That never happens correctly.

If you can locate your boot drive in the Finder and do a quicklook on it, that should report the actual free space. Select the disk and hold down the space bar. It should look like this:

Ignore anything that says “available” space.

I was finally just resolving a major problem with my iTunes Library in the Music App when my previously working Mail App threw me this error. I'm thinking I really should've waited on loading Catalina. Sigh.

I'm finding an identical issue since my Catalina upgrade. 27 (of 50) GB free on my iCloud drive and 243 (of 1120) GB free on my hard drive.

I get the error sooner and sooner the more I space I free up on my drive (emptying the trash gave me ~100 GB - it had been a while!)