MacBook Pro 13-inch (Intel) reboots with 'Windowserver' crash after installing macOS Tahoe and activating screensaver

No issues here on 3 different computers I Own and Operate with Tahoe 26.0. 26.01 or now 26.1

Part 1 of 3

Restart the computer in Safe Mode 

Do the issues persist ?

Sometimes a Safe Boot followed by a Normal Boot will just put things right.

If not - there could be something in the main User Account playing up. To further isolate this - Set up users, guests, and groups on Mac. Then log out of the Main User account and log into the dummy account and test again if the issue persists.

If the issue is present in the dummy account - then, this appears to be a System Wide issue on the computer.

Part 2 of 3

To Drill Down further and to avoid a session of Q&A, Q&A  and Q&A  

Download the Application Etrecheck  ( External Link ) directly from the Developer.

The Application is Not a " Silver Bullet "  and is  only a tool to examine the Hardware / Software used on this computer 

This is a Diagnostic Tool that makes no changes to the computer Hardware / Software used on this computer 

The application is free or paid from added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - copy and paste - >>>> using the Additional Text Icon ( 3rd Icon to last ) <<<<

Part 3 of 3

User Risk Assessment: macOS Downgrade Procedure

Before initiating any downgrade from macOS 26 (Tahoe) to an earlier version such as macOS Sequoia, assess the user’s tolerance for potential risks. The following checklist must be completed before proceeding.

Primary System Dependency

Determine whether the affected Mac is the user’s primary or only computer.

If the user cannot function without this system for several days in the event of a failed downgrade, the risk level is high.

The downgrade should be postponed or avoided until proper contingency measures are established.

Availability of a Secondary macOS System

Confirm that the user has access to another Apple computer currently running macOS 15 or macOS 26 (Tahoe).

This secondary system must be capable of performing a Revive or Restore operation on the target Mac’s firmware if required.

Lack of a secondary Mac significantly reduces the ability to recover from firmware corruption or boot failures.

Firmware Compatibility and Secure Enclave Risks

Be aware that upgrading to macOS 26 (Tahoe) likely includes a firmware update affecting the logic board and Secure Enclave Processor (SEP).

Downgrading to an earlier version (e.g., Sequoia) may introduce firmware mismatch issues, leading to instability or loss of functionality.

There have been at least three documented cases where downgrading from Tahoe to Sequoia resulted in Secure Enclave malfunctions, requiring full system restoration or hardware servicing.

Backup Integrity and Recovery Preparedness

Verify that the user has at least three complete backups created before the macOS 26 (Tahoe) upgrade.

Implement the 3-2-1 Backup Strategy:

3 total copies of essential data

2 different backup methods or storage media

1 copy stored offsite (for protection against natural or human-caused disasters)

Each backup should reside on a dedicated, single-purpose external drive.

For enhanced backup and cloning capabilities beyond Time Machine, refer to:

🔗 https://bombich.com

Recommendation Summary

If the user answers NO to any of the above questions:

Downgrading the Mac is not recommended.

Proceeding without proper contingency plans, verified backups, and recovery tools may result in:

Data loss

Firmware corruption

Secure Enclave failure

Complete system inoperability

1) Did you get to try the same situation in Safe Mode? Does it also crash?

2) I can see from the report that there are many VERY old third party extensions - going as far back as 10.5 Leopard - that is extremely old.

It is no wonder that one or more very old system extensions may fail to work on an OS that is about a decade and a half newer than the one for which they were programmed.

Among those you have "Duet" - a very old software that used to allow things that are now supported directly by the OS, like using an iPad as a screen for your Mac. I bet that it does stuff that messes with windowserver at a very low level. Not saying it is the culprit, but it deserves to be uninstalled, to see if something changes.

Really, what I think it should be done is:

1) multiple backups

2) erase all content and settings

3) migrate ONLY the user accounts

4) install fresh the applications that you do need

This will leave behing all that older stuff that you almost surely don't use but could causing trouble.

FWIW. This may not be helpful, but I just wanted to let you know that my 2020 MacBook Pro has experienced a similar issue with the WindowServer service. These all started with macOS Tahoe as well. I reviewed several "app crash" and "kernel panic" reports and determined the issue, for my case, was that "hardware acceleration" option was enabled in my Brave web browser. Once I disabled it, the crashes stopped.

Test Tahoe On a Clean Installation

This is a prepared reply that I do keep handy just for such occasions as this one

Do what you believe is best for the computer which does not always align with what the users explications

If the user ( you ) believes these current issues stem specifically from macOS 26 Tahoe.

For a thorough test to determine if Tahoe is the root cause of all computer issues.

Apple Intel computers >>   Use Disk Utility to erase an Intel-based Mac followed by How to reinstall macOS

Always make a Time Machine backup before proceeding.

Run the computer without installing any additional software and without restoring from your Time Machine backups.

Run the computer in this mode for approximately 6 to 8 hours and report back if the previous issue reoccurs.

Within a timeframe ranging from a few seconds to a few minutes after the screensaver activates, the screensaver freezes, the screen goes black and the default wallpaper appears with the instruction to enter my password to activate touch ID.

This is exactly what I saw. It definitely points to an application crash, and not, a kernel panic. I do understand that this is still happening with a clean install of macOS ... so, it is quite possible that the troublesome app is from Apple.

At that point all previously open windows quickly reopen and finally a crash report appears entitled "Window Server experienced a Problem" followed any about a kilometre of text (more than the 250,000 characters I am able to attach here as "additional text")

If you are game, I would be happy to review the app crash report. I would only need the first third of the report so it should easily fit into the "additional text" tool. These reports should appear in the Crash Reports section in the Console app.

Discard the Etrecheck application and the report it generated.

Discard the suggestion entitled “Test Tahoe on a Clean Installation.”

The original poster wrote, “They then started talking about possible logic board issues (caused by updating the OS - really?)”

Given the concerns expressed about the logic board, a more thorough investigation is required to either confirm an issue with the logic board or refute this assertion.

Have the computer evaluated by professionals, who possess the specialized hardware and software expertise to diagnose the issue.

It should be made known that, in most cases, they will first wipe the drive and reinstall a new version of Tahoe. Then they will examine the results. Depending on their findings, they will proceed with specialized hardware testing. 

emteeell wrote:

I've already sent countless of these bug reports to Apple anonymously. Do you suggest I send one by another means?.

At this point, I am referring to using Apple's Feedback Assistant. If you participated in any of the Apple beta programs, it would already be installed on your computer. If not, then they have an online version, located here:

• https://feedbackassistant.apple.com/

However, if you have been sending them "bug reports," this may not be necessary. The key is to provide Apple with as much detail as possible to "grab their attention". FWIW, I have fouhd that when doing so, I have received replies from the Apple Engineers.

If you want, I can provide you with some input material to use with the Feedback Assistant for this issue.

emteeell wrote:

I know you were trying to be helpful but I don't think you have read my post thoroughly. I've done a lot of troubleshooting and spent a lot of time talking to Apple. Looks like you've copied and pasted something. I draw your attention to all the steps I have already taken, all followed by "made no difference", in particular the creation of a new volume onto which I installed Tahoe 26.1 via Recovery mode, which made no difference either:

"I've spent maybe 8 hours on various calls to Apple tech support trying to sort it and they obviously have no idea what to do. I was variously told to remove all start up items(made no difference), empty caches, delete saved states, delete preferences, delete all Safari extensions etc. (made no difference) and create a new user (made no difference). I finally got the case escalated to the senior team who told me to create a new volume and install Tahoe on it (made no difference). They then started talking about possible logic board issues (caused by updating the OS - really?). When I said I just wanted to downgrade to Sequoia, they said that might "cause problems" (oh the irony) but didn't really explain why."

If we may point out, the User is Technically Replying to themselves

An offer of assistance has been offered

What the Recipient does or does not do , is entirely up to them