Is a new MacBook Air necessary for efficient email handling with a large email collection?

Half a million email messages is about a half million too many for me, but even several times as many is not unheard of.

Lyn Murdock wrote: ... I have more than a million and half messages accumulated over 20 years, housed in thousands of individual mailboxes.

And that was ten years ago!

How to transfer mailboxes from V4 (Sierra) to V3 (El Capitan) - Apple Community

Obviously your relative's Mail app is consuming a lot of CPU cycles though, apparently resulting in some degree of unresponsiveness. To address it I suggest rebuilding the affected Mailbox, or all Mailboxes if necessary. Hopefully she has less than thousands of individual Mailboxes.

Apple buried the instructions for rebuilding Mailboxes in a more comprehensive Mail Support document whose title doesn't even hint at it, but here is an archived version: Rebuild mailboxes in Mail on Mac (Archived). Two steps.

Be advised rebuilding Mailboxes is time-consuming even for a more realistic amount, while Mail re-downloads every single message from the email server(s). Consider several days a very rough estimate.

Should go without saying, back up all data before doing anything. Back up your files with Time Machine on Mac - Apple Support

Assuming you're using IMAP/SMTP, these emails aren't on the Mac anyway. So space isn't the real issue.

The problem is the absurd number of emails the OS and email client have to try and display in its lists. That means every bit of available RAM is being clobbered, and is very likely spilling over to a large block of virtual RAM on the drive.

I once activated all 38,000 fonts I have just because to see what would happen. Not surprisingly, the Mac slowed down a bit, but apps with font lists became nearly unusable. Particularly if I tried to select anything in the font list. I can't imagine what nearly half a million entries would do to performance.

You'd have to have a monster of a computer to reasonably handle a list like that. As in, at least 128GB of RAM and the fastest CPU you can get. Basically, a gaming PC with a $500 video card, a minimum 1 TB SSD to handle virtual RAM, a seriously overclocked CPU and as much RAM as the board will let you install. Or said another way, a very overpriced email terminal.

What I would do is get those emails onto a completely different server where they are converted to regular files and are searchable through a front end via a web browser so the server is doing the work instead of a greatly overworked email client on your end. Once built and tested, clear out the email server. Either that, or someone has to determine how many of those emails even need to be there anymore and delete as many as possible. Or, at least archive up to 80% of the oldest ones. I can't imagine anyone looks at anything more than a couple of year old very often.

Limnos wrote:

Relative has a 2019 Macbook Air 500GB drive 16GB  RAM. Drive is half empty. Checked Activity Monitor and memory is green. Checked cpu and it is green too though 147% of the two cores is taken up by Mail app alone. She has access to research institute’s entire 450k emails. Complains that despite things being in green that even typing a reply in mail may have letters appear very slowly. Scrolling also very lagged 

Not sure if it would help getting newer MBA or if any version of Mail just can’t handle that size collection even if system reports no problems. 

I think the type of email for those 450K emails matter. IMAP versus POP, for instance. Or if using MS-Exchange, that works but somewhat irregularly with Apple Mail, and my employer has MS-Exchange and while we use Outlook by fiat there, I also have used Apple Mail. Apple Mail was always MUCH slower than Microsoft's Outlook, for instance, with Exchange email systems.

If she is using POP for those 450K emails, she can archive all but the most recent few years, and that would remove them from Apple Mail, although any desired can be retrieved. If the 450K emails are IMAP, then that could be very taxing for the Mac if there are many mailboxes.

I think working with 450K emails on a 2019 Macbook Air is probably not a plan that is conducive to success. Macs will slow down when the number of files, folders etc. gets that large. Ultimately, each email is one file and there are many nested folders in Apple Mail.

Keeping 450,000 emails directly connected to one's personal computer or smartphone seems like a good setup for causing performance problems with any machine.

Thank you everybody for your replies! I am now back home so I can't help my relative with this anymore directly. One of my suggestions was to buy a new MBA and see if the problem persisted. If it did then take advantage of the 2 week return period and try another solution. The IT department at the place where my relative works said that this was a "known issue" with Apple Mail and to use some other application of which I had never heard (probably something PC based).

Hi,

I'm still using 2018 MacBook Pro without the problem at all, though!