PSA: Apple Mail Bugs Can Lead to Data Loss in macOS Catalina

mailappiconMichael Tsai, the developer of EagleFiler and the SpamSieve plug-in for Apple Mail on Mac, has written a blog post warning macOS users about potential data loss in Mail when upgrading to macOS Catalina 10.15.0 (build 19A583).

According to Tsai, he's heard from several users that updating Mail's data store from Mojave to Catalina sometimes says that it has succeeded, when in fact on closer inspection it turns out that large numbers of messages are incomplete or missing entirely.

In addition, users have reported the loss of message content when moving emails between mailboxes. From Tsai's post:

Moving messages between mailboxes, both via drag-and-drop and AppleScript, can result in a blank message (only headers) on the Mac. If the message was moved to a server mailbox, other devices see the message as deleted. And eventually this syncs back to the first Mac, where the message disappears as well.

Tsai warns that these issues are particularly pernicious because users may not realize anything's wrong unless they look at affected messages or mailboxes. Since the data is synced to the server, these problems can also propagate to other computers and devices, and relying on backups is difficult because Mail data is continually changing and there's no easy way to merge restored data with messages received since the last backup.

Despite the latter risk, it's still good practice to make backups, but Tsai notes that Apple Support appears to be erroneously advising users that lost Mail data in Catalina can't be recovered from a Time Machine backup made using macOS Mojave.

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

Tsai says he's unsure whether these issues are due to Mail bugs or to other factors such as problems on the Mac or with the mail server. Apple released macOS Catalina 10.15.1 beta to developers on Friday, but it's still unclear if this version resolves the Mail app bugs. Regardless, Tsai's advice to users who rely on Apple Mail is to "hold off on updating to Catalina for now."

Affected readers can find the full breakdown of the issues here. Have you had problems with Mail since updating to Catalina? Let us know in the comments below.

Related Forum: macOS Catalina

Popular Stories

iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro Coming Soon With These 14 New Features

Friday July 4, 2025 1:05 pm PDT by
Apple's next-generation iPhone 17 Pro and iPhone 17 Pro Max are just over two months away, and there are plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models. Latest Rumors These rumors surfaced in June and July:Apple logo repositioned: Apple's logo may have a lower position on the back of the iPhone 17 Pro models, compared to previous...
iphone 16 pro models 1

Here's How the iPhone 17 Pro Max Will Compare to the iPhone 17 Pro

Saturday July 5, 2025 1:00 pm PDT by
Apple should unveil the iPhone 17 series in September, and there might be one bigger difference between the Pro and Pro Max models this year. As always, the Pro Max model will be larger than the Pro model:iPhone 17 Pro: 6.3-inch display iPhone 17 Pro Max: 6.9-inch displayGiven the Pro Max is physically larger than the Pro, it has more internal space, allowing for a larger battery and...
iPhone Car Key Kia

Here's Which Vehicles Offer iPhone Car Keys

Sunday July 6, 2025 3:03 pm PDT by
In 2020, Apple added a digital car key feature to its Wallet app, allowing users to lock, unlock, and start a compatible vehicle with an iPhone or Apple Watch. The feature is currently offered by select automakers, including Audi, BMW, Hyundai, Kia, Genesis, Mercedes-Benz, Volvo, and a handful of others, and it is set to expand further. Apple has a web page with a list of vehicle models that ...
imac video apple feature

Apple Launching These 15+ Products Later This Year

Sunday July 6, 2025 8:05 am PDT by
The calendar has turned to July, meaning that 2025 is now more than half over. And while the summer months are often quiet for Apple, the company still has more than a dozen products coming later this year, according to rumors. Below, we have outlined at least 15 new Apple products that are expected to launch later this year, along with key rumored features for each. iPhone 17 Series iPho...
iOS 26 Feature

Everything New in iOS 26 Beta 3

Monday July 7, 2025 1:20 pm PDT by
Apple is continuing to refine and update iOS 26, and beta three features smaller changes than we saw in beta 2, plus further tweaks to the Liquid Glass design. Apple is gearing up for the next phase of beta testing, and the company has promised that a public beta is set to come out in July. Transparency In some apps like Apple Music, Podcasts, and the App Store, Apple has toned down the...
iphone 17 pro render majin bu

New iPhone 17 Pro Renders Highlight Apple Logo and MagSafe Design Changes

Sunday July 6, 2025 8:43 pm PDT by
New renders today provide the best look yet relocated Apple logo and redesigned MagSafe magnet array of the iPhone 17 Pro and iPhone 17 Pro Max. Image via Majin Bu. Several of the design changes coming to the iPhone 17 Pro model have been rumored for some time, such as the elongated camera bump that spans the full width of the device, with the LiDAR Scanner and flash moving to the right side. ...
iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro to Reverse iPhone X Design Decision

Monday July 7, 2025 9:46 am PDT by
Since the iPhone X in 2017, all of Apple's highest-end iPhone models have featured either stainless steel or titanium frames, but it has now been rumored that this design decision will be coming to an end with the iPhone 17 Pro models later this year. In a post on Chinese social media platform Weibo today, the account Instant Digital said that the iPhone 17 Pro models will have an aluminum...
Prime Day 25 Feature Warm Triad

The Best Early Prime Day Deals on Apple Products

Saturday July 5, 2025 7:22 am PDT by
Amazon is soon to be back with its annual summertime Prime Day event, lasting for four days from July 8-11, the longest Prime Day yet. As it does every year, Prime Day offers shoppers a huge selection of deals across Amazon's storefront, and there are already many deals you can get on sale ahead of the event. Note: MacRumors is an affiliate partner with Amazon. When you click a link and make a ...
airpods pro 2

AirPods Pro 3 to Help Maintain Apple's Place in Earbud Market Amid Increasing Low-Cost Competition

Thursday July 3, 2025 7:25 am PDT by
Apple's position as the dominant force in the global true wireless stereo (TWS) earbud market is expected to continue through 2025, according to Counterpoint Research. The forecast outlines a 3% year-over-year increase in global TWS unit shipments for 2025, signaling a transition from rapid growth to a more mature phase for the category. While Apple is set to remain the leading brand by...

Top Rated Comments

cardfan Avatar
75 months ago
Looks like Apple has their own windows Vista.
Score: 75 Votes (Like | Disagree)
Apple_Robert Avatar
75 months ago

Who is heading the Mail department? I want him fired.
Newman is the head of the mail department.
Score: 61 Votes (Like | Disagree)
Geert76 Avatar
75 months ago
macOS Catalina is one OS to skip. Never read about so many bugs and other problems with a release of a fresh new macOS.
Score: 55 Votes (Like | Disagree)
Khedron Avatar
75 months ago
Can all the people defending Apple like "it's ok to brick your system it's only beta" now wake up and see Apple has a software development problem that is getting worse and worse
Score: 51 Votes (Like | Disagree)
TrenttonY Avatar
75 months ago
Good thing Apple had a beta to iron these critical bugs out!
oh wait...
Score: 45 Votes (Like | Disagree)
jafd Avatar
75 months ago
One would think a trillion dollar company could afford a QA department with people that are actually competent.
Score: 39 Votes (Like | Disagree)