I'm using A1 Click Ultra. It has been doing this ever since I bought the lap top a year ago. After doing a clean I get the two dialog boxes which I have to close before it will start. Then in about a week it starts normally.
The dialog boxes don't give any indication as to which files they are referring to.
What are you clicking on in A1Click Ultra PC Cleaner? Clean PC, Remove Tracks, Run Settings, Registry Cleaner, some thing else? It sounds like your computer is not allowing A1Click to delete a file. You might watch where A1Click's scan is and maybe that would give you an indication of where the files are.
I assume that when you say, "until the next time that I try and start it", that you are talking about starting A1Click. A1Click does delete the old undo files when it starts. It sounds like your computer is not allowing those files to be deleted.
I don't know how that could be coming from A1Click. Maybe something else is causing that. The only possibility that I can think of is if one of the startup items is located in the temporary directory or the files that it uses are located there. I would suggest looking at your startup items and see which one could be causing that.