Each site has its own
__Download folder on the client. The one that is locked would be for whatever site contains the source fixlet of the Offer that is giving this response.
Generally a locked __Download folder means a previous action spawned a ‘wait’ or ‘run’ command for a program in its __Download folder, but the program never terminated. You should be able to find the active program in Task Manager and terminate it, to allow the folder to be cleared and used for the next action.
A stuck process usually means a setup command was run without the command-line parameters needed for a silent/unattended installation, and it attempts to launch a graphical interface/wizard for the user to click ‘next’ through the installation options, but as the process is running in LocalSystem context it cannot display that interface to the interactive user session; instead, the dialog just remains ‘stuck’ until the process is killed or the system is rebooted.