Hello. I had switched phones with my sister and decided to reset the Samsung GT-i5700R to factory settings as well as format the SD card. When I inputted my Gmail account and password, I went to download an app in the Market. It began to download until a notification came up: "Download was unsuccessful, please try again." I read up on the other topics about this, and I tried the following already: Tested downloading Google apps to see if it was just that app, and it didn't work Cleared the cache of the Market application Cleared the data of the Download Manager application Force stop the app then cleared the cache/data of the above apps Factory reset the phone Signed in another Gmail account and password If anyone has an idea, I'll be willing to try. Edit: I have Android 1.5 as my firmware. Edit #2: I don't know how or when exactly it started working, but it's fixed. I'll list what I had done in case it helps anyone. I went to Settings > Applications and made sure that checked Unknown Sources. I went to slideme.org on my phone's Browser and downloaded Fast App Installer. Then I executed it, and it worked perfectly. I proceeded to downloading more apps from SlideME, this time onto my SD card, so that I can install them using Fast App Installer. A couple hours later, I tried to download an app using Market and it was successful. I was able to install use it, and it was the same for all apps following it. In the end, I believe that the phone just needed to sync completely with my account, and then Android Market. Hope this helps.