Apple Mail error can cause data loss in macOS Catalina

Michael Tsai, developer of EagleFiler and SpamSieve plugin for Apple Mail on Mac, wrote a blog post, warning macOS users about the possibility of data loss in Mail when upgrading to macOS Catalina 10.15.0 (build 19A583).

According to Tsai, some users who updated Mail's database from Mojave to Catalina thought that everything had been successful, but actually when a closer inspection, it turned out that a large number of emails were updated incomplete or were completely missing.

In addition, users have reported losing mail content when moving emails between mailboxes. According to Tsai's post:

"Moving mail between mailboxes, both with drag and drop, can create an empty mail (header only) on a Mac. If mail is delivered to the server mailbox, other devices will see that the message has been deleted. And finally, this syncs back to the first Mac where the email also disappeared. "

Tsai warns that these issues are especially dangerous because users may not realize anything is wrong, unless they look closely at the affected emails or mailboxes. Because the data is synchronized with the server, this problem can also spread to other computers and devices. Besides, relying on backups is difficult because Mail data is constantly changing, and there is no easy way to merge restored data with emails received since the last backup.

Although risky, it is still advisable to make a backup. However, Tsai noted that Apple Support seems to be misleading users that Mail data lost in Catalina cannot be recovered from Time Machine backups created with macOS Mojave.

According to Tsai, this is not the case that Apple Mail's File> Import Mailboxes . menu bar options can be used to selectively import them into Mail in Catalina as a new local mailbox.

Tsai said it's not certain whether the problem was due to a Mail bug or other factors such as a problem on a Mac or mail server. Apple released ‌macOS Catalina‌ 10.15.1 beta to developers on Friday, but it's unclear whether this version will fix the bug in the Mail app. Regardless of the cause, Tsai's advice for Apple Mail-based users is "to suspend updating to Catalina right now".

Affected readers can find complete information on issues at:

 https://mjtsai.com/blog/2019/10/11/mail-data-loss-in-macos-10-15/ 

Have you had problems with Mail since updating to Catalina? Share your comments in the comment section below!