How to fix Messages app closing after macOS Sequoia 15.4 update?

Found the source of my problem, and indeed it's a different issue. Somewhere in the past, I sent some stickers from a sticker pack that came with an app on my phone. But the app (and hence the stickers) are not on my Mac. Deleted the stickers from the conversation on my phone (which still had the app on it) and now iMessage has no issues anymore.

This happened to me, too, on June 6. I have an iPhone and two Macs (both using iMessage in iCloud). My iPhone was fine, but iMessage on both of my Macs was stuck and non-responsive, even after multiple force quits and SAFE mode restarts.

After reading this thread, I noticed a mention of a sticker. The last message I had received was from an old thread that included a Thanksgiving Peanuts sticker. I could delete this message on my iPhone and M2 MacBook Air without any problems, but my M1 iMac was stuck and wouldn’t let me delete the message or get iMessage stable.

What finally worked was:

1. Restarting the computer.
2. Turning off iMessage syncing in iCloud.
3. Restarting the computer again.
4. Deleting the iMessage databases in the Library folder.
5. Restarting the computer a third time.
6. Opening iMessage.

After these steps, iMessage was empty but stable. I then reenabled iMessage syncing in iCloud, and iMessage synced all my messages (except the one with the sticker that caused the issue). It has remained stable since.

AdminVDS1 wrote:

Since updating to 15.4 my messages ap and Podcast app on my mac just shut down. They don't appear to crash since I don't receive a pop up stating the app has crashed. I don't appear to be having issues with any other apps. Suggestions on how to repair or fix?

Couple things— you can try launching the app while holding the Shift key down, and compare your results...

no change try a SafeBoot Start up your Mac in safe mode - Apple Support to sort anomalies

Login and test. Reboot as normal and test. Caches get rebuilt automatically.

15.5 appears to have resolved this for me - my problematic trio of apps (Messages, Tapestry, Mona) have not spontaneously shut down since I installed the update yesterday afternoon.

I had the same problem since updating to 15.4. Upgrading to 15.4.1 did not solve the problem immediately. However, I added message app to allow "Full Disk Access" under Privacy & Security. Since then, message app has been running without closing!

Have you updated to macOS 15.5? That seems to resolve the issue for at least some people (myself included).

The 15.5 update absolutely worked for me.

No longer does the iMessage app close on its own.

I’ve left it open for days after the update with no issues.

updated to 15.5 has stopped the issue for me

I ended up formatting and going with a fresh install, reinstalling apps and everything is working again. my guess is that something must have gotten corrupted, this was my oringal install that has been upgraded quite a few times. also was from an intel based MBP before I upgraded to my M4 pro.

So can anyone who has (or, optimistically, had) the problem confirm or deny whether the 15.5 Update fixes this issue?

Meanwhile, this AppleScript checks every 20 seconds to see if Messages is running and relaunches it if it's not:

-- Script to monitor if Messages is running and launch it if not
property checkInterval : 20 -- Time in seconds between checks

on idle
	-- Check if Messages app is running
	tell application "System Events"
		set isRunning to (exists (some process whose name is "Messages"))
	end tell
	
	-- If Messages is not running, launch it
	if not isRunning then
		try
			tell application "Messages" to activate
			log "Messages was not running. Launching now."
		on error errMsg
			log "Error launching Messages: " & errMsg
		end try
	end if
	
	-- Return the number of seconds to wait before next check
	return checkInterval
end idle

on quit
	continue quit
end quit

Paste the above code (h/t Claude.ai) into a blank script window in Script Editor and save it as an Application. Be sure to check the checkbox for the "Stay open after run handler" option. Then just run the script application and leave it running.

I had seen that 15.4.1 didn't seem to fix the issue, but my MacBook Pro didn't shut anything down automatically for at least a couple days after I installed the update. Then, suddenly, I came back to it after a couple hours yesterday afternoon and it had shut down Mona, Tapestry, and Messages while I was away (so, that's one Apple app, one 3rd party Mac app, and one iPad app).

Also, to clarify: the apps in question are not "crashing" (there is no "XXX shut down unexpectedly" message), they're being shut down automatically by macOS in much the same way that iOS/iPadOS automatically shut down apps to preserve RAM or battery. However, this is new behavior in macOS 15.4 - I haven't seen macOS automatically managing system load by shutting apps down previously, though Apple has been preparing to possibly enable it for some time (by allowing you to turn off the indicator for running apps in the Dock). Like many here, I keep a lot of apps open (I use Mission Control/Spaces pretty heavily), but if you turn off that running apps indicator and usually use one app at a time via the Dock, you might never notice this happening.

Ironically, this is kind of a variation on the bad habit some people have of force quitting apps on iOS/iPadOS to "preserve their battery", which just causes a heavier battery hit when the apps are restarted from scratch every time. In this case, though, it's macOS shutting apps down on devices that generally have more resources than mobile devices, and might even be plugged in.

Finally, if apps are immediately shutting down when you try to open them or your entire OS crashed, you're dealing with a different problem.

This sounds like something different than the random Messages (and other app) closing that this thread is addressing. This sounds like a memory issue, especially if you have messages going back more than four years - not saying it isn't a bug, just that all those beach balls indicate that the app seems to be waiting on data and becoming unresponsive. You might want to check memory usage in Activity Monitor's Memory tab to see what is actually happening when you try to load those long conversations.

Did you try safe mode reboot? Any positive results?

Thanks

I've read on Reddit I think it was that adding the crashing Apple apps to Full Disk Access can solve the problem until the next OS update is released.