Trying to get a Property Checkpoint on the little popup that appears just above the clock in FF 3.6 when a download is done -- the little "All Downloads Complete" thing that pops up and then goes back...
We reproduced a similar behavior, but need to be sure whether that's exactly what you faced. Please answer the following questions:
1. Does TestComplete becomes responsive again after a few minutes when you catch the popup window?
2. If it does not, what OS is installed on the problematic machine and what steps you followed to reproduce the behavior (do you start recording before capturing the object? do you use the Finder tool to capture the object?)?