When updating the system, sometimes a new mail folder is created called, “On My MAC”. What causes this folder to be created and what is it. When checking the subfolders, there is no mail displayed. As I understand it, the purpose is so that I can store mail or drafts to this folder if, for some reason, I do not want them on the mail server. I haven’t been able to find much information on this subject. Any info is very much appreciated.
Can the “On My MAC” folder and subfolders be deleted?
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William Johnson
This is an email mailbox (database of messages) that exists only on your Mac. So some local messages stored on your hard drive. The messages in here are not part of any online email account like iCloud, Gmail, Outlook, IMAP, etc.
If you move a message from one of these email services, into "On My Mac," you are removing it from that server's database of messages and storing a copy of it locally.
If you don't want to do this (I never use it myself) then you can just ignore it. You can delete any empty mailbox folders inside it if you wish. You can also click the button to the right of it that appears when you move your pointer there, and hide all of the folders under it.