I can only download one file at a time even though I am an Ultimate user

Open the Transfers window and check the column Status for the file which is not being downloaded. If the file is Queued by you, make sure you have maximized the number of Downloads : Options > Traffic > Downloads/Total maximum=Max. If the file is Queued by a contact, just wait until your download reaches the … Read more I can only download one file at a time even though I am an Ultimate user

Download doesn’t work: Queued by …

Open the “My Transfers” window and check the column “status” for the file which is not being downloaded. Download is queued by me:Make sure you have maximized the number of Downloads :  Options > Traffic > Downloads/Total maximum=Max. Download is queued by my contact:Just wait until your download reaches the top of your contact upload list

How can I stop an upload?

You cannot stop a specific upload. However, you can limit the number of simultaneous uploads by going to the transfer options (transfer tab/modify transfer behaviour). You can even change the number of uploads to 0 to stop all of your uploads.