still have the same problem with After effect 2020 version 17.1.2
Horizontal guide makes it impossible to work at all!
Can somebody help?

I've found the bug has gone away... hasn't troubled me in a while.

Same issue here on:

iMac Retina 5k Late 2015 running macOS High Sierra 10.13.6
After Effects 16.1.3 Build 5

Tried the workaround Felix suggested but it did not work for me.
Every click is painfully slow.
For a better understanding – my guides are imported/embedded in PSD files.

In AE Preferences -> Display:

"Hardware Accelerated Composition, Layer, and Footage Panels"

Turn it off to test if that helps to get back normal performance.

I have the same issue with any composition I create. The vertical guide performs absolutely fine but the horizontal one makes the comp extremely laggy. I'm also running Mojave and the latest version of AE. Not sure if a test project would work as it happens with any composition I create/open.

Could you possibly send us a very simple test project where the bug happens for you? We'll need to get an internal repro of this before we can make any progress toward fixing it. Thanks in advance.

16.1.1 (Build 4). I'm working on a Mac Pro with Mojave 10.14.4

As far as I know, it's the most recent software. There are no available updates.

Thank you for that recording, Colby. Which version/build of Ae are you running?

Here's a screen recording of the behaviour: https://we.tl/t-lkY0MaiMKu

Hello Colby,

I have not heard of this bug before - would it be possible to make a screen recording and/or pass along a project that demonstrates this behavior?

Thanks for taking the time to post about this behavior.