I'm not sure I totally understand the question. In your Lib window, select the incomplete folder & press Refresh. If you press Refresh every so often you can see the incomplete file size increase bit by bit each time. All your incomplete files will remain in this folder until they have completed dwnlding, when they will transfer to your dwnld folder. Actually yo can check your incomplete folder on your HDD to see if the incomplete files are still there. What's in that folder will be reflected in your LW Library window when Incomplete folder is showing. Make an alias to your LW dwnl folder (CMD+L) & put it somewhere easy to find (eg-in the dock or desktop, top level of user doc folder, etc.)
Also double-check your Dwnld folder location (LW Prefs-Saving) & make sure nothing has changed.
Can you double-check your LW version again. I'd suggest if you're using LW v.2, you 'might' have some problems depending on your OSX & Java version. The present version is 4.