Hello all,I have a problem with Vista and Outlook on my work network. The issue is that when attempting to send a mail with a Non-Text attachment, the mail sits in the Outbox and takes a very long time (hours for 1MB) to send. During this time, no other mail is sent or received on the client. The problem occurs with attachments above 20K, though I usually use 100K for testing. This occurs over a wired connection only. If you have a wireless connection (either built-in, or with a USB wireless dongle), and the wired connection is disabled, the attachments will send immediately.Here is a breakdown of info that may help, and also things I have tried:Environment (All with latest updates): Windows 2003 Domain Exchange 2003 Server Wireless-G WAPsClients: Windows Vista Ultimate, Enterprise, or Business (x86 and x64) Outlook 2003 or 2007 Several different Hardware models, for example: Dell GX620, Dell 745, Dell 755, Dell GX280, Thinkpad X61, Thinkpad X41, Dell D530 There is no additional software being installed, only a Vista install, then an Office install, and then the updates.Weird Things: If you set the Wired connection to 10/Full Duplex or 10/Half Duplex the e-mails will send. If you set the Wired connection to 100/Full, 100/half or Auto the e-mails will not send. If you use the Wireless connection with default settings the e-mails will send. If you create a 1MB Text file (with or without .txt extension) and attach that to be mailed, the e-mail will send. Other file types of the same size will not send. If a mail is stuck in the outbox not being sent, when you Close Outlook, the outlook process does not stop. If a mail is stuck in the outbox not being sent, and you exit Outlook (via end process), then disable the Wired Connection, and enable the Wireless connection the mail is sent as soon as Outlook is launched.Things I have tried: All settings of Vista Autotuning With and without Vista Service Pack With and without firewall disabled Flow Control in all settings Priority and VLAN enabled/disabled Various Driver from MS and Manufacturer Power Management on/off With and without any group policy settings appliedHas anyone else ran into an issue like this? Does anyone have any ideas on how to resolve this? Everything works fine on Windows XP that's why I am posting in the Vista Networking Forum.Thanks in advance for any assistance.Corey

Hi Corey, According to your description, the issue is more Outlook related. I suggest you post the question on Outlook forum. For your convenience; Clients Topics discussed include: Outlook, OWA, and other clients http://forums.microsoft.com/TechNet/ShowForum.aspx?ForumID=835&SiteID=17 The reason why we recommend posting appropriately is so you will get the most qualified pool of respondents. Thank you for your understanding.