Updating to 2004 left me with broken task scheduler. I was able somehow to get it back by updating to 20H2 and running the last (after dozen of times before updating) sfc /scannow by miracle. I had no idea what fixed it but hey it was working so ok. NOW all of a sudden task scheduler is givin the SAME ERROR as before, AGAIN. It's unbelievable.
The last thing my PC has done that I can associate to this problem is a quality update for 20H2. I can't find absolutely nothing on the internet. I have performed all the scannow and DISM stuff many times now. No issues have been found. I have also used a restore point previous the last couple windows updates but it didn't work.
Initially, by trying to start the "schedule" service it reported the "1067: the process terminated unexpectedly" error, so the service won't start. Now the service starts but when openin task scheduler the "remote computer not found" message appears, and task scheduler won't be able to read anything from my PC. (The remote computer of course is the local one).
Startup for the "schedule" service is set to automatic and has never been changed.
Task scheduler is inaccessible even through elevated CMD, as typing "schtasks" or "schtasks /query" do both result in "wrong network address".
This is RIDICULOUS. I really hope Microsoft can do something about this and stop messing up with my PC.
[SOLUTION] Recap: my Task Scheduler service wouldn't automatically start even though the service startup was set to automatic both in Services and Registry. If I tried manually starting it I would get either errors (see above) or fake starts (the service resulted as running but would not be picked up as such by e.g. Disk Defragmentation Utility).
While a commonly proposed solution was adding a "start" key in the registry to set the automatic service startup [value: 2] (in my case it was already present), I edited the value to 3 [manual startup] (since the option to change the startup behaviour is greyed out in Services). So now my Task Scheduler service is set to manual startup and it starts up at boot and everything related to it works as intended (at least for now).