Make the wait time to 5 seconds. If the new Explorer window does not show up under this delay, I display a message "Do you want to continue waiting or proceed with next folder without changing the position and size of this window?". If the user answers "Wait", I wait another 5 seconds. If he chooses "Proceed with next", I give up for this folder (the window will eventually show up but it will not be positioned or re-sized) and I start loading with the next folder in the group.
Make the wait time to 5 seconds. If the new Explorer window does not show up under this delay, I display a message "Do you want to continue waiting or proceed with next folder without changing the position and size of this window?". If the user answers "Wait", I wait another 5 seconds. If he chooses "Proceed with next", I give up for this folder (the window will eventually show up but it will not be positioned or re-sized) and I start loading with the next folder in the group.