MacBook Pro Screensaver Stutters After Latest Tahoe 26.3 Update

Thank you for posting the EtreCheckPro report.

macOS does not require any third-party junk-ware to stay safe and clean.

see > Apple Platform Security

Uninstall BitDefender, CleanMyMac (aka BreakMyMac) and the VPN as per those developers directions.

Then redo the Safe Mode startup followed by a normal restart and test.

"The funny thing is that my work computer, which is a brand new MacBook Air on Tahoe 26.3 is working fine. "

I think it makes sense that the MacBook Air isn't affected because I suspect the problem stems from ProMotion 120Hz (if you disable it and switch to 60Hz, it works perfectly).

I have the exact same problem with all animated screensavers on a MacBook Pro M4, but not on a MacBook Air M2.

Startup in Safe Mode and let it soak for 10 minutes. Then restart normally and re-test the ScreenSaver.

see > Start up your Mac in safe mode - Apple Support

Then if shuttering and glitches still happen or come back after a short time.

Download and run the free version of EtreCheckPro, from > https://etrecheck.com/en/index.html

Then post back here with your Report, as per > How to use the Add Text Feature When Post… - Apple Community

Such a blank statement. I can confirm that it has to do with variable refresh rates or pro motion. When I deactivate pro motion and leave it to 60 hz or disable VRR and leave my external monitor to 165hz It works. As soon As I activate it again, it starts again. This has started after the update to macos 26.3 .

[Edited by Moderator]

I total concur with my colleague @ den.thed 👍

From your @ Greggs21  Etrecheck Report 

1 -Bitdefender

2 - com.macpaw.CleanMyMac5

Part 1 of 2

There are two schools of thought when dealing with CleanMyMac aka “ BrickMyMac “

Be aware, once this type of application has been installed and used on the computer

It will never work the same without doing a " Start  Over from Scratch " 

The steps in #1 below is predicated on the Offending  Application, CleanMyMac , has been Removed as per the Developers Specific Instruction 

# 1 Some Contributors suggest restarting in Recovery Mode and choosing to Reinstall the Operating System over the existing installation. 

This may or may not replace elements of the  Home Folder ( User Account )  and replace any corrupted or removed elements and make things right.

#2 - Then there are Other Contributors ( like myself ) would suggest  from this link Use Disk Utility to erase a Mac with Apple silicon.

Thereafter to start from scratch and install all Required Applications directly from the Apple Apps Store or Directly from the Developer.

If going this route - I suggest Not using Startup Assist to migrate things back as this will probably Re-Introduce the existing  issue at the time TM Backup was made 

Part 2 of 2 

Certain Applications maybe available on the Apple Apps Store - this only means the Developer is prepared to pay Apple a percentage on each sale. 

What the Application may do to the computer is up to the User to check this out before purchase

Any of the below should be removed as per Developers Instructions 

Disk Cleaner 

CleanMyMac , aka “ BrickMyMac “

Third Party Security Software 

This will include BitDefender

There are no known Windows-like Viruses in the wild that self replicate and affect macOS, because of the underling UNIX  Foundation and Permission Limitation. 

The Operating System resides in a Sealed and Read Only Volume that cannot be opened by the User nor by Third Party Applications.

The Only thing this Antivirus software is protecting is the Bank Account of the Developers and for zero return to the User aside from the problems this software creates.

Security. Built right in

Mac app security enhancements

The Built in Security  is all that is required to protect the computer.

Protecting against malware in macOS

This has nothing to do with needing to clean your Mac or with Antivirus software. I have changed nothing since the update and am experiencing the same thing. I have no AV software installed. This has to do with the last update. The same thing happens if I close everything. Same thing happens if I reboot and test.

MacBook Pro M3 Pro 12-core / 18GB RAM

I experience the same problem, even after restart. Screen saver ran smooth like butter in previous version but with the recent update screensaver stutters and screenlock responsiveness to display the login is laggy.

Can't test after safe mode re-boot though, as i have work related tabs open which I can't loose at the moment.

Specs:

MacBook Pro 14"

Apple M4 Pro 14 Cores

48GB

macOS Tahoe v26.3 (25D125)

I also have an M4 Pro MBP (16", 48 GB memory) and no issues with the screensaver on 26.3. Same on my M1 Pro MBP. Different screensavers, doesn't matter whether the display is the internal or an external 5K:2K.

I think my response to you has all the information that I have. It's related to the variable refresh rate, or promotion and is probably a Tahoe 26.3 launch bug!

AntiVirus software will provide False Positives

That is a know fact

Email attachments are a vector to plant Malware

Malware does Not Automatically Get Installed

To get installed, would require You ( the User ) to have Purposefully and Knowingly Give the Malware Authorization to Bypass the Builtin XProtect

Malware defences are structured in three layers:

1. Prevent launch or execution of malware: App Store or Gatekeeper combined with Notarization

2. Block malware from running on customer systems: Gatekeeper, Notarization and XProtect

3. Remediate malware that has executed: XProtect

As for browsing the web. ?

From one of our Senior Contributors on this very topic

Thank you @ John Galt

https://discussions.apple.com/docs/DOC-8841

👍

🦉-53