And

In my case the problem seems to be solved by adding "Recovery" to the list of exclusions

Alfred is the latest version now 5.0.5 [2096]

Reset done

Right after reboot everything is fine. When I do "eject all" after couple of hours, I've got the same

What else can I try?

Alfred 5.0.4 Build 2095

MacOS Ventura 13.0 (22A380)

Happens almost every time I'm using ejectall command

I often see the same behaviour both in Mojave and Catalina it is actually related to TimeMachine. In my case they do show in the eject menu, and "Eject All' gives corresponding errors

Alfred 4.0.6 (1124)

Features -> System -> Blacklist:

Macintosh HD

MobileBackups

com.apple.TimeMachine*

Did reset there, didn't help

Steps to reproduce: start a TimeMachine backup