The Issue
Shortly after a file download via Google Chrome for Windows completes, the download will get stuck on "0 seconds left" and all other programs (except Google Chrome, for some reason, but browsing will not work) completely freezes into Windows' infamous "Not Responding" state, affecting Explorer particularly badly. Eventually, the programs will recover themselves but they will recover significantly faster if you cancel the file download, relative to how quickly you react.
Performing the exact same operation immediately after cancelling the download usually works without issue.
This issue occurs when with any file type (.ZIP, .MSI, .MSG, .PNG, .URL, etc) of any size from any source (Dropbox, SourceForge, Imgur, even tiny and locally-generated BLObs created by my own Chrome extension, etc) to any location.
Potential Causes
As this issue is so inconsistent, I haven't been able to prove whether the issue is Chrome-specific or being caused by my system or my Chrome configuration but it's happening on both my work and home PCs.
I originally suspected that this issue was being caused by security software scanning completed downloads for threats but I'm not as confident in that theory anymore as the issue persisted even after changing my security software from ESET NOD32 and Malwarebytes Anti-Malware Pro to ESET Endpoint to Microsoft Security Essentials.
System Information (of both PCs)
Windows version: 7 Service Pack 1 64-bit
Google Chrome version: 30.0.1599.101 (but has been happening for a long time)
Screenshots