Many users have reported that they are not able to download updates. The 'Search for updates' reveals updates, but they cannot be downloaded. Often a 'HTTP Error 403' or 'bad checksum' is displayed. This has a simple reason - millions of people trying to download from the same server, which can't handle such a burden. In combination with the growing size of the detection file this is becoming a serious problem.
We are currently considering possibilities to improve the situation. This includes the search for additional servers and ways of more effective compression. At least one server will soon be added, others will follow hopefully.

In order to overcome the problem for now, if you try again, have a second look at the menu bar. It has a pull-down item to select a mirror. Click the arrow beside it, and select a different location, where you'll most probably have better chances to download.