Mac Mojave Sys Prefs/Screensaver slows down, locks up

Hi, I had exactly the same issues it’s all started after Mojave Security Update 2020-004 & it affects screen savers with photos in them.

My solution for now is to use the Message/Text screen saver for now my device won’t keep freezing but it’s annoying that an update missed up an Apple system screen savers.

Same here. Any saver that uses a folder of images, be it Apple-created or user-created, will do it. I'm using Shell and it works.

Be sure to report this to Apple. They won't see your concern here. They WILL see problems reported using this Feedback link:

https://www.apple.com/feedback/macos.html

Historically, that method has been very effective.

Yes! It is now fixed.

I found downgrading to original Mojave wasn't viable. I forgot that over the past year or two updates have made irreversible changes to our firmware, such that the updated firmware conflicts with older macOS versions. My Mac was creating firmware .dumb files!

Now all updates available applied as of 12/24 and the problem is fixed. I think fix was in Security Update 2020-007 Mojave https://support.apple.com/en-us/HT212011, released 12/14/20.

Same here just after latest Security and Safari update ..i updated about17th of July 2020

Loading screensaver makesmy Mac (Retina 5K, 27-inch, 2017) unresponsive for felt 2 minutes; even happens when i open preferences for screensaver; the issue occured with landscapes; switched now to flury .. seems to solve it in preferences it does not slow down .. hope it keeps in normal use.

(tried another user account on my computer .. the same happenes with landscapes

iMac (2019), 10.14.6 - I had the same issue. I knew that the problem was Mojave Security Update 2020-004, because a bootable backup made before the update did not show the problem. After much troubleshooting, I reinstalled the operating system by booting up using Command-R. That reinstalled 10.14.4, which I then updated to 10.14.6. The reinstalled OS did not include Security Update 2020-004, and the screensaver now functions normally.

Same issue noted here shortly after installing security update 2020-004 (July 2020) on both a MacBook Pro (early 2015) and a MacBook Air (early 2015) with the default collection folders. Thanks for the direct feedback link. Bug Report submitted.

UPDATE: Since the latest update to Safari 14 there seems to be an improvement, but i am not sure if this is randomly btw placebo-effect ;(wondering about what Safari got to do with the screensaver but as Safari is somehow part of the system software there may be some correlation)

Waiting for the screensaver when activates takes about 15 seconds. But still not ok because during this time the computer cannot be used.. The process stalls everything for at least 15 seconds. Happens when just looking for the screen-saver-settings in preferences and when screensaver is activated scheduled or by hot corners.

After the last update today has the problem gone away for anybody here?

For me NO, still the Computer becomes unresponsible for 10 too 30 seconds and more

Especially when u just load the photobased screensavers in preferences A process like Ilife showing about 30% CPU usage

Sorry yes , i was distracted after posting, now editing of my fault is not possible.

No improvement.. still my mac becomes unresponsive for up to a minute.

i have this on 2 Macs (my imac and my wife`s Macbook pro.)

From software revision "Big Sur" the screen is filled with an ugly bright RED and Orange screen......at least with Catalina it was a picture of the island -- here we get pop-art .

I have set one machine to just go to black screen, but I would like to randomly show travel pictures --

TY for ur Information! Please report here:

https://www.apple.com/feedback/macos.html

as Allan Jones recommends.

May an update by Apple follow soon.

well for Mojave the bug is solved now by the update of today; hope u got one too!?

https://discussions.apple.com/thread/251596661?answerId=254132073022#254132073022

I'm having the same issue here on my Mid 2012 Mac Pro running 10.14.6 -- submitted my bug report today. Hopefully we'll get a fix soon.

FWIW, the security update broke all photo-based screen savers. The workaround for now is to select any non-photo screen savers, Flurry, Shell, Message, etc.

SOPRRY Problem NOT solved; it takes too long until my mac gets responsive when dealing with these photobased screensavers.