Screen saver freezes mac + very high CPU usage

I see the same thing. Here's how to tell Apple about it--they won't see your problem posted here

Go to this feedback link:

Feedback - macOS - Apple

When you fill out the form, select these pulldown options:

The feedback link is the only way to get this fixed, short of writing a snail-mail letter. Posting here gets us nowhere.

I have the same issue with screen savers that have photos, it’s all started after Mojave Security Update 2020-004.

my temporary solution 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.

Keep reporting it. Over and over. Not everyone appears to be having this issue so we cannot sit back and wait for someone else to act.

Use this link and be sure to explain that this started with the 2020-004 update:

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

Last update some days ago, (Suplemental update, Security + Safari) did not solve the issue, as i saw i another thread here it is Apple recommended to use one of the none photo related screensavers

https://discussions.apple.com/thread/251589096?answerId=253891573022

Hiya...

Yes, I am having the same issue across both iMac and MacBook Pro. The issue seems isolated to those screensavers that display photographs. At least for a temporary workaround, you might consider shifting to "Flurry," or one of the other other non-photo screensavers.

It's interesting that you found the "ilife slideshow" app behavior....Apple hasn't referred to its home software as iLife in years...someone definitely screwed something up. Very strange for a late "dot" release of last years MacOS.

I'm having a similar experience with two newer MacBook Airs on 10.14.6. None of the screensavers involving photos work, regardless if they're my own or the ones Apple provides. System will completely freeze up for almost half a minute (even the clock's seconds freeze up). If I preview it, it's a black screen and takes several seconds to snap back after cancelling. I experience the same issue during Safe Boot, from separate user accounts and after trashing all Screensaver plists.

I believe the issue started yesterday after installing Security Update 2020-004.

after a safe reboot it somehow seemed to improve after switching back normal boot.; but still when i go to preferences> screensaver it makes my whole computer unresponsive for a while if Sierras i activated; it loads very long and u cant do anything with teh cpmputer in the mean time;

For a day it worked better when sccreensaver activated automatically; the delay untill u can work was sometimes ok.

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.

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)

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.

That was the first thing I checked after applying Security Update 2020-005. No change. Attempting to select the Ken Burns effect screensaver or my preferred folder for a screensaver still freezes my computer for about a minute, and doesn't appear to successfully complete. I was wondering if maybe the screensaver app needed to be authorized within Security & Privacy's Full Disk Access, but I couldn't add it there.

Security Updates 2020-004 & 2020-005 also broke the ability of my MS Office 2019's AutoUpdate app to successfully apply updates to my Office apps.

Many bugs, including Permission problems from the 2020-005 SecUpd, the recent supplemental Update cured things for many, others need to reinstall Mojave though in a Safe Boot...

Safe Boot, (holding Shift key down at startup).

I just did the safe Boot again. then tried to load the sreensaver (Sierras, Landscapes) and it stalled the Computer for a short time (10 seconds)

but the window in preferences Screeensaver stayed black.

After reboot there seemed for me shorter loading time for the mentioned screensaver.

I am in good hope that the problem might be solved now.. just in the phase of testing, for i want to avoid a reinstall.

Today an update appeared AND.. have a guess.. BUG IS GONE! 😀 😊👍

(it was a security and a Safari update; i dont know what it was called.)

same here see also thread

https://discussions.apple.com/thread/251589096

seems to work with flury , landscapes- themes have the describeds issue