macOS Catalina extremely slow to Lock and Unlock Mac using fast user switching menu

I was experiencing the same issue with slow login and lock/unlock after a clean install of MacOS Catalina. After troubleshooting I noticed in the Activity monitor while accessing Users & Groups or Security & Privacy that the process listed below was consuming an unusually high amount of RAM. Normally uses 25-30MB RAM and was using between 600MB and 1GB.

com.apple.preferences.security.remoteservice (System Preferences)

The problem in my case seems to have been a corrupted user profile photo. The profile photo was selected from the User & Groups for the user experiencing the issue. When creating a Test User this issue was not experienced. After changing the profile photo to a MacOS default image and testing lock/unlock the process mentioned above was back to using 30MB of RAM and the system was very responsive both with the password and unlock using Apple Watch. Changing back to the user selected photo the issue returned and would take ~8-10 seconds to unlock.

I'm guessing this was a photo file corruption of some kind as we are able to select other photo's from the Photo's app and they worked without re-creating the issue.

I'm still investigating the issue, but in my case it's the WindowServer process taking 100% CPU when switching to another user - or even just changing from the 'one user lockscreen' to the one with the list of icons of all users.

Thanks for posting this, chasing the picture worked for me too. My previous profile picture was 69Kb, so no idea why that would have caused an issue but swapping to a default image has solved the issue.

Thanks again :)

I was just able to fix this issue on my MacBook Pro: even tough all user icons were picked from the defaults provided by the OS, one of them were zoomed. It looks like replacing that one with a default and "unedited" photo fixed the issue for me as well. Thanks again for the hints.

Changing my profile picture (actually just selecting the same photo from disk) fixed this issue for me (10.5.3 19D76). I was getting both slow login and also very slow root authentication prompts. Both are instant now. I love it when fixes are easy. Thanks!!

Thank you very much this resolved it for me. Had an identical issue with the slowness and changing to a default profile photo fixed it instantly. Almost too good and easy once you know it. :)

Thanks again for giving me a normally working mac again!

(and to note I was experiencing this on Catalina 10.15.3

I just got the MacBook Pro 16 a couple of days ago and has similar issue from the beginning.

Changing the picture as mutineer612 suggested worked!!!! I was about to return the laptop but this saved it. Thanks!

Thank you so much for the advice. As soon as I changed my profile photo to one from the default set, my slow log-in and password dialogs immediately went away. I was waiting up to 30 seconds at times just to authenticate to make a change to a setting.

I was having this issue, and interestingly I was able to fix it by changing my user photo. System Preferences > Users & Groups > Edit photo. Apparently my photo was an image that was quite large (maybe 11 MB), and switching to a smaller one of less than 1 MB completely changed the experience, and I no longer have those delays.

Good luck!

If you are using an app like https://www.alfredapp.com/ you must uninstall and reinstall again. I experienced the same thing and it's what fixed my issue on the extremely slow lock and unlock

I had the same problem! I had a profile picture at a resolution 2.000x2.000, I resized it at 640x640 and now everything is fast and snappy!! Thanks!

I'd like to additionally prove that the problem was in profile photo. I've changed the profile photo to default one and everything now works like a charm! Thank you, @mutineer612! 😇

What do you mean by default photo? You picked one from the stock photos?