Last post was way back in November but in case anyone reads this thread and has tried the suggestions without a full restore of their apps, here is my (positive) experience:
First of all---yes I tried the items suggested here multiple times and in different orders---my issue may be compounded by the fact that I am not using the original SD card.
(skip to the MY WORKAROUND paragraph if you are in a hurry--don't want background story)
I encountered the Download Unsuccessful issue more and more frequently once I replaced my original SD card (wouldn't have replaced it, but it began misbehaving, as did my son's on the same model: Droid X).
Yesterday I lost more and more functions and decided to do a factory reset. Once I entered my google account info, the market went crazy trying to push all my previous apps to my phone (even those I had long ago removed), and it seemed nothing would stop them from being pushed. The humorous thing is that the apps were supposedly being sent to my phone, but each one resulted in the message 'Download Unsuccessful'; the loop could have gone on for hours.
OTHER THINGS I TRIED that may be ENOUGH of a solution for others:
*uninstalling the android market update
*deleting the cache from the market app
*deleting the data from the market app then re-associating the market app with my google account
*multiple re-boots
*multiple factory resets
*wiped the dalvik cache
*formatted my sd card
*pulled my sd card THEN tried to download market apps
I (thought I) resolved this by wiping the phone yet again, and NOT re-adding my old account. I made a new google account and thought everything was fine; was happily downloading multiple free apps and setting things up. Then I realized the Google Market associates the first account placed on the phone with the market and all those downloaded apps with that account too. I'd previously spent over 80$ on software and use it and wanted it back.
MY WORKAROUND:
First of all I downloaded the Opera Mobile app via the built-in browser. That let me download other apks. If this doesn't work for you, be sure your Settings: Applications: Unknown Sources checkbox is CHECKED. From Opera Mobile, I was able to download the AppBrain apk. I wanted to download the Fast Web Installer apk directly too, but the App Brain link took me to the Market software (which we want to stay away from)
SO I USED OPERA TO GO TO:
https://market.android.com/ I signed in to the market web site with my google account I had purchased all my apps through. I located Fast Web Installer and grabbed the apk. I went back to AppBrain and activated the Fast Web Installer. Went to the AppBrain website and clicked through the list of apps I remembered (that were free) and chose INSTALL. They were PUSHED to my phone which was slick.
I got to my previously paid apps via that market link:
https://market.android.com/ and by doing a text search for the apps I wanted to re-install. Since I was logged in, the 'Purchased' status was visible and I could click the 'Purchased' phrase to re-download my paid for apps. The crappy part is that my troubleshooting took so damn long. But the end solution is not that difficult actually!
...
