Windows 7 - Download Hang

Hello,

I work in the IT department of a manufacturing company and I'm having an intermittent issue with downloading files. The computers on my network running Windows 7 Professional 64-bit (With or without SP1) are the only ones with the problem, Windows XP computers work fine.

When I try to download a file, the download starts out fine but then just stops. The download speed gradually goes down, the time remaining gradually goes up, and the amount downloaded stays the same. I have a screenshot of a download that is currently hung up, the time remaining has gone to 4 minutes since the screenshot (20 minutes ago) and the speed has gone to 180 KB/sec. The screenshot is of a download with Firefox but the same thing occurs with Google Chrome, IE8, and IE9.

Also attached is a screenshot of a speed test as well as a screenshot of my "ipconfig /all" output. This doesn't always happen, but it happens plenty enough to impede my work some days. If I restart the download enough times, it will eventually finish but could take up to twenty tries (That's about the highest of gone before just going to an XP machine to download the file). It happens on all Windows 7 machines on the network but never on a Windows XP machine. My router is a SonicWALL NSA 240 and my ISP is Comcast. Comcast has replaced the modem and tested the line with no abnormalities.

Thank you for any assistance and please let me know if you need any more information.

All browsers are up to date. I have Internet access when the download hangs. To verify, I had a continuous ping going during the download and had 0 packets lost whenever the download stopped.

I edited the ipconfig attachment and re-uploaded it. I would guess that is why you couldn't see it when you tried to look at it. Sorry about that.

I tried it on a fresh installation of Windows and it does the same thing. Tried clearing cookies/cache and still the same thing. I'm usually pretty good and troubleshooting but this has me at a loss.

almost sounds like an Ipv6 QoS issue

The download also hangs in Safe Mode with Networking. I'll look into QoS settings for now, I didn't set up the router so it may take a bit to find. But in the mean time, I'm open to any more suggestions or advise.

What do you mean by a IPv6 QoS issue? Is it something you've seen before and what causes it?

Okay. It looks like no QoS is configured on the router.