Using a download manager to download from an MSDN subscription

I called BizSpark support about this problem, myself. Not sure if you're based in the UK, but the guy on the phone said they'd just fixed a problem they'd had with their UK servers last week, so maybe things will be better now.

He also suggested the following workaround/"fix" (valid wherever you are):

1. Only ever use Internet Explorer to download from BizSpark (*sigh*)
2. In Microsoft File Transfer Manager click on Options. Then click on Connections and make sure that HTTPS is UNticked.

He said this cleared up problems for a lot of people and sped up transfer rates.

This all worked for me, so hopefully it will work for you. (Remember to double check the hashes of the files you download -- a corrupt .iso can cause all kinds of weird and wonderful problems.)

I also discovered that the UK support number on their website is wrong (yay, Microsoft), use the MSDN team number on 0800 051 7215.

Hope that helps!

The download managers don't require the server to support resuming

That's not correct. If a server doesn't support resume then download managers cannot resume downloads.

When is Firefox going to finally add the ability to resume downloads

Firefox does resume downloads. The problem is that many servers refuse to resume downloads even if there's a break in connection - the time period differs from server to server. ( TED's servers immediately comes to my mind, if there's break in connection for about 5 seconds, the download is ruined and I have to restart the download from start.)

I just tried Free Download Manager (FDM), again, having the Firefox addon Flashgot use it. The download gets passed to FDM, and fails, giving the error message "access denied, invalid username or password.

I also tried DTA instead of FMD with Flashgot, and I get an "access denied" message in DTA.

Few servers inspect the HTTP headers for the referrers, and block if the referrer is not a browser. I guess while transferring the download, the header gets mangled and the referrer becomes the download manager, instead of the browser.

The failure message in the Firefox Downloads window is source file at http... could not be read.

That's become the download links are autogenerated, are valid particular combination of parameters ( perhaps some session id ? I'm not sure), and are not persistent. Once the control of the download has been handed over to the browser, the links expire, and hence you get the error message. My suggestion: Try IDM. It's one of the better download managers that I've used. If the problem still persists, my suggestion is to use an alternative link to download, or maybe switch to a wired connection while downloading.