Screen saver freezes mac + very high CPU usage

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.

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.

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.

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).

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

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 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.

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.

Please report here : Feedback - macOS - Apple

as Allan Jones recommends; May an update follow soon;

it was update2020-007 15.12.20

same here, even the non-photo screensaver options are extremely slow

great temp solution Falcoon, worked for me ;-)

Thank you, i sent a report!