UPDD Commander must have permission to control the computer and will not load unless this is set:
A user upgraded their system to 10.15 Catalin and this in some way affected permissions such that the system indicated permission was set but permission dependant requests failed as in this example :
The user unchecked and rechecked the UPDD Commander entry and all was OK.
If this does not resolve try deleting '-' and adding '+' UPDD commander:
Incorrect listing
In addition to the above, we are also aware that UPDD Commander will sometimes be listed in System Preferences > Security & Privacy > Privacy > Input Monitoring, (we are not sure what triggers it)
If this happens, it's necessary to grant it input monitoring permissions otherwise it can't monitor keystrokes, and it'll produce the error message that's being reported.
When UPDD Commander is granted Accessibility permission (given permission to control the computer) in the main Accessibility dialog that covers both using the Accessibility features *and* monitoring keystrokes. Unfortunately, if Commander gets added to the input monitoring list, it now requires that permission as well as Accessibility permissions in order to run.
Adhoc resigning
This should never be required, but we had a user that could only use Commander if the system was connected to the internet, otherwise they saw 'keyboard event filtering error' show above.
Commander is a signed/notarised application, but in this case we think there was something very subtly wrong in regard to the signature that was making this one particular system reject the signing credentials and needed to connect to the internet to verify it. We had the user re-sign the app using what's called an "ad hoc" signature that doesn't require a certificate, and apparently that was enough to get things working as expected on his system.
- Remove UPDD Commander from the list of apps in Security & Privacy.
- Connected the computer to the internet.
- Run this terminal command:
sudo codesign -s - --force --timestamp "/Library/Application Support/UPDD/UPDD Commander.app"
​Unfortunately, it is possible that a future installation might experience the same issue and need ad hoc signing again.