Hangs and cannot be closed

Tried running the portableapps version of Toucan on Windows 7.  Tried to sync a directory with around 200BG for data.  Seemed to run normally for a brief period but then the progress records (i.e., looked like what would be written to log file that cannot be found) stall and nothing happens.  Could NOT stop it from running.  Shutdown was prolonged for some time before finally completing.