I've been unable to download or update any applications or songs on any of my phones, ipads, or imacs. I just keep getting the messages, "Unable to download application." It's been this way for weeks. What can I do?
iPhone 4S, iOS 5.1.1
I have noticed this issue too. I am playing my music through iTunes Match on my computer at work, and this annoying error message comes up every so often.
At first I thought it was related to iTunes Match not being able to play some songs (because it would skip some), but it just seems to happen regardless of what's going on with iTunes Match.
I will try it again on a different computer (and different network) to discard a potential firewall/proxy issue and post back what I find out.
Have you received an answer for this? I have been getting an 8003 error on two updates to apps, and when I tried to fix that via iTunes support for that error (deleting the Downloads folder), I am now getting the 1003 error.
Actually, I just fixed it. I uninstalled iTunes altogether, then changed c:\users\username\My Music\iTunes\ to c:\users\username\My Music\iTunes.bak and reinstalled iTunes. After I reinstalled iTunes, I re-synced my iPhone and then right-clicked my iPhone name (in iTunes) and selected Transfer Purchases and it put all of my music and apps back in the iTunes folder on my PC. I then checked for updates and it downloaded and installed all correctly.
I've been getting this error with iTunes 11.1.3(8) -- latest version. I've avoided by de-selecting simultaneous downloads.
This coincides with log messages such as:
sandboxd: ([###]) xcscredd(###) deny file-read-metadata /Users
sandboxd: ([###]) apdpd(###) deny file-read-metadata /Users
iTunes: Possible unresolved transaction race -103/(iTunes/iTunes Music/Downloads/Netflix.tmp,(null))
iTunes: Possible unresolved transaction race -103/(iTunes/iTunes Music/Downloads,(null))
(yes, 103 above, yet 1003 error code, perhaps no relation)
The "transaction race" makes me think there's a Mutex that's being un-gracefully-waited-for, and the bail-out message is simply a 1003.
As a workaround, I've disabled/unchecked "Allow simultaneous downloads" in the download dialog (if you click the down-arrow in the upper-left of itunes window, the dialog shows you the downloads in progress/completed/pending; this checkbox is at the bottom) ...
So far, no recurrences, but we'll see.
Unable to check for available downloads. An unknown error occured (1003)
