This issue started a month or two ago and it has vexed me ever since. Whenever I download a file from IE or FF, or save an attachment from Outlook 2010 and save to my desktop the file does not show up until I either right-click and choose "Refresh" or hit F5 to refresh the desktop. The same thing happens when I extract a .zip or .rar file to my desktop, doesn't matter the contents of the archive, whether they be files or folders, nor the quantity extracted. It also doesn't matter how many times I download files to the desktop or extract items from an archive, until I refresh my desktop the downloaded files/extracted items remain hidden. This does not happen if I choose any other location as my save to destination - the file shows up immediately upon completion of the download or extraction process. Also this doesn't happen if I copy/paste a file or folder to the desktop. It shows up immediately as normal. Also, if I right-click and create a new folder, or document, etc. it also shows up right away without having to refresh the desktop. If I delete a file or folder it disappears immediately without having to refresh.
I don't use any download managers, this is a relatively new install of Windows 7 Professional Retail, only about 6 months old, all updates have been installed, and I'm not sure what other information you might find helpful to solve this issue. My user folders (Documents, Downloads, Music, Videos & Pictures) reside on a different HDD other than the OS drive and I have changed the properties to point to their locations on the other drive but that was done immediately after installation of the OS. The Desktop folder and its contents still resides on the OS drive. I'm not sure what other information I may be forgetting to include in this post that you may find useful but please let me know if I can provide you with any other details.