What has happened to my Apple Mail?

[blackxacto]

24” M4 iMac 10 core 16gbRAM, macOS Tahoe 26.6.1, Fiber Internet connection.

Apple Mail has started refusing to send more than one attachment at a time. The attachment was only 20mb. If I send 3 email attachments that aren't more than 50mb added together, Apple Mail refuses to send, and says Mail Drop is busy, come back later. But if I send one email w one attachment of 20mb. Apple Mail goes WHOOOSH its gone.

I use 60gb of 200gb iCloud storage. What the heck is happening that I have to break up attachments one at a time? Why is Apple closing my mail "tunnel".

 

[Bigwaff]

Have you reached any Mail Drop limits?

https://support.apple.com/en-us/108329

 

[blackxacto]

50mb is not 5gigs? How am I supposed to know if I ever reach a limit if Apple won't tell us what we have used?

 

[berb]

Could be the recent iCloud outages. Mail wasn’t able fetch my emails this morning, said server was busy, but now it’s working fine.

 

[benholt]

The Mail Drop trigger is per-message combined size, not the overall 5GB storage cap — and the per-message threshold is around 20MB. Three attachments totaling 60MB crosses that automatically, so Mail routes the whole message through Mail Drop instead of just SMTP. The 'busy' response is Apple's undocumented per-user upload throttling that kicks in way before you'd hit the storage limit; it usually resets over a few hours.

Couple of workarounds worth trying. Zip the attachments together into a single archive first — if that drops the combined under ~20MB, Mail sends via SMTP and never touches Mail Drop. Doesn't help for already-compressed formats (JPEGs, most PDFs) but works for RAW, docs, or CSVs.

Cleaner option: right-click the files in Finder → Share → Add People to generate an iCloud Drive share link, paste that in the message body. Skips Mail Drop entirely, doesn't count against the throttle, and the recipient just clicks a link.

If you want to see the actual throttle bucket that's tripping in real time, open Console.app and filter for MailDrop or com.apple.MailKit while attempting the send. The busy responses are logged with which quota bucket got hit.