For this sort of thing you may be able to use a Menu condition or a Found Image condition.
Since you probably do not need a quick response to the completion, and you don't want to use a lot of CPU, rather than:
- Pause Until Found Image condition is true
Do something like:
-
Until
- Pause 10 seconds
- Found Image condition is true
I use a similar sort of thing to press the “Finish Scanning” button when the scanner is finished scanning my page. In this case, I use the Button condition, and since I don't much care about the CPU for that period of time, I just use the Pause Until action.

Look at the available Conditions to see if any of them can be used to detect the completion.