Haven't found a satisfactory answer to this, though David91 had good input in his post "Don't worry about the tone thing"

Uploads *never* exceed 1 or 2 percent, according to my Monitor window. It's no skin off my nose; I'm not a philanthropist or anything. Also I understand many reasons why uploads don't reach 100 percent. But I do observe some things that make me go "huh?":

1. Almost all my uploads appear as a duplicated pair in my Monitor window.
2. Uploads progress in fits and starts, e/ period of apparently active data flow never lasting more than maybe half a minute.
3. When uploads that have stalled at 1 or 2 percent resume, the completion percentage goes back to 0 or 1 percent upon resumption.
4. Many inactive uploads say "Complete" at 1 or 2 percent, but then resume uploading anyway.
5. If my active window is not the Monitor window and I see by my internet connection software that a lot of data is flowing outward, and I switch to the Monitor window to observe the uploading, I can see all active uploads suddenly stopping, like cockroaches scurrying for cover when you turn on the light. Sometimes they resume if I keep the Monitor window active.
6. Many if not most uploads from me are of relatively obscure song files, so it's hard to believe that *absolutely all of them* could be 1 or 2 percent contributions to transfers from other folks.

-Platform: Mac
-Connection: modem
-Quality: always either Excellent or TurboCharged
-Upload bandwidth: 100% (tried 10% too)
-Slots: tried various settings, no difference observed
-No firewall, no LAN, no school, no nothing.

Interesting.

If you were on broadband, you've described what happens when ISP's filter uploads. The first bits get through, then the filter stalls them for 60 seconds or so and the packets are lost.

You can see this on the Tools->Statistics->Bandwidth->Upstream graph pretty clearly.

BUT, I've never heard of ISP's doing this with modems, so I'm stumped. Send a screenshot to your ISP of the graph, and ask for their suggestions. Maybe they just give modem connections a lower priority, and so the effect is the same?

If you want, PM me with a magnet of the file (control click the file in the library to get the magnet link) and I could let you know what happens if I try downloading it.