After upgrading to macOS 15.3.1, many users encountered sudden and persistent crashes in core applications like Mail, Calendar, Notes, and more. These issues have caught even technically proficient users off guard, mainly because they affect applications that are deeply integrated into daily workflows. Although Apple has not issued an official fix at the time of writing, a growing number of users on forums and support communities have discovered a temporary—but highly effective—workaround using an alternate admin account.
TL;DR
If core macOS apps like Mail, Calendar, and Notes are crashing after upgrading to macOS 15.3.1, you’re not alone. A known bug seems to affect user-specific configuration files. Creating a new admin account on the same Mac allows the apps to function normally, suggesting that the issue is tied to the original user profile. This workaround has helped many users restore functionality while Apple works on a formal patch.
Understanding the Problem
Shortly after the 15.3.1 update rolled out, users on Apple’s Discussions forums, Reddit, and other tech communities began reporting app instabilities. The majority of reports center around:
- Mail app crashing immediately upon launch
- Calendar failing to open or freezing during use
- Notes not syncing or becoming unresponsive
In more severe cases, system-wide slowdowns and sandbox permission errors pop up in diagnostics logs, pointing to corrupted preference files or incompatible metadata introduced during the upgrade. Because these issues are tightly linked to the user profile, traditional remedies like rebooting, reinstalling macOS, or even clearing app caches do not resolve the problem fully.
Why This Happens
The theory supported by developers and IT administrators is that macOS 15.3.1 introduced subtle changes to how macOS handles user-specific metadata and sandboxing. These changes might have rendered older configuration files—like those found in ~/Library/Containers—incompatible or unreadable. Since these preference and cache files are user-specific, the corruption or misconfiguration does not affect the system itself, only the profile under which the upgrade was performed.
The Alternate Admin-Account Workaround
This workaround, while not a permanent fix, effectively bypasses the corrupted or misconfigured files tied to your primary user account. By creating a new administrator account and logging in under that account, the system generates a clean user environment with new preference files, solving the issue for most users.
Step-by-Step: Create a New Admin Account
Here’s how to do it safely:
- On your main user account, open System Settings.
- Go to Users & Groups and click the “+” button.
- Select Administrator as the type of the new account.
- Enter a name, username, and password. Click Create User.
- Log out of your primary account and log into this new account.
Once logged in, launch the problematic apps like Mail or Calendar. In many reported cases, they work normally, without crashing or freezing. This proves that the root cause is tied to app data or metadata in the original user profile.
What You Can Do From the New Account
Even though this does not restore your full setup, the temporary admin account can be used for essential tasks until Apple pushes a permanent fix. Here’s what users commonly do:
- Use Mail and Calendar normally – You can configure your system-wide email and calendar accounts temporarily on this profile.
- Copy files from the broken account – The new admin account has access to the old user’s files (with permission changes, if needed).
- Run Time Machine or other backups – A clean account can perform backups without file lock issues caused by corrupt processes.
Permanent Solutions (When Available)
Apple is likely aware of the issue, given the significant number of support tickets and forum posts. Though they have yet to release an official patch, users should monitor the following update sources for possible resolutions:
When a fix does arrive, it will likely require either an automatic patch delivered through the Software Update utility or a step-by-step user intervention. In either case, staying informed will help you transition cleanly when the time comes.
Risks & Considerations
While the alternate admin-account method works for many users, it’s important to exercise caution:
- Don’t delete your original account – It still contains essential apps, files, and possibly system-level configuration references.
- Avoid excessive customization on the temporary account – Keep it minimal to reduce complexity when switching back.
- Be careful with preference files – Avoid manually moving or replacing preference folders between accounts unless you fully understand what you’re doing.
In professional environments, IT administrators should also avoid mass profile resets or large-scale profile migrations until Apple acknowledges and corrects the behavior.
Advanced Troubleshooting (For Developers and IT Pros)
Experienced users who wish to delve deeper can try isolating the exact component that’s crashing. Tools like Console and Activity Monitor can help identify whether crashes occur due to sandbox violations, missing entitlements, or corrupt container data.
Commands to investigate:
log show --predicate 'eventMessage contains "Mail"' --info
ls ~/Library/Containers/com.apple.mail
plutil -p ~/Library/Preferences/com.apple.mail.plist
Warning: Any modifications to plist or container files can result in data loss or app instability. It is not recommended unless under professional supervision or for advanced debugging only.
What Apple Users Are Saying
The Apple community is actively sharing stories and workarounds. According to one highly-upvoted post on the Apple Developer Forums:
“Switching to an alternate admin account was the only thing that worked. Every other advice from Apple Support failed, including disk repairs and safe mode. Three days in, the temporary account is still running flawlessly.” — dev_mac_33, Apple Dev Forums
It’s reassuring to see consistency across these anecdotes, hinting that the solution is genuine and not just a one-off case.
Conclusion: Use the Workaround, Stay Informed
Crashes in core macOS apps like Mail and Calendar can utterly derail both personal and professional productivity. While it’s frustrating to deal with app instability after an update, users aren’t entirely without options. Creating an alternate admin account provides a practical path forward until Apple releases an official update to address the bug. Avoid drastic measures like downgrading or wiping your Mac unless absolutely necessary.
In the meantime:
- Use the new account for daily tasks.
- Back up your data regularly.
- Keep monitoring official Apple channels for updates.
Until macOS 15.3.2 or a hot patch is released, the alternate admin-account method remains the most dependable solution available.