I was doing some testing (3.9 build 1249 Lite) on a W7 x64 Virtual Machine with "Reserve disk space for downloading file" un-checked and DLing a large file (3.3 GB W8 Preview) and the DL stalled for a few minutes then started up again. I opened the Task Manager-Performance tab-Resource Monitor and observed the disk activity when I started the DL. What I saw was a several minute write by fdm.exe. A rough calculation indicated it was writing the entire 3.3 GB file while the DL stalled because no space was available for the data. A Wireshark trace shows my machine sending [TCP ZeroWindow] responses to the server causing it to time out and close all the ports with [RST]. Is FDM really writing every byte of the file and why? Thanks and enjoy, J.