Feb 1, 2012
After downloading the new OS for my Blackberry 9780, I installed the OS on my laptop running windows 7. As a regular Blackberry device OS up-grader, I am used to follow these regular steps:
1. locate the downloaded OS, run as administrator and install the OS on my laptop
2. uninstall the previous version of blackberry device OS.
3. delete vendor XML in folder C: > Program Files > Common Files > Research In Motion > AppLoader
4. run the Desktop Manager software, and after connected just click Update.
unfortunately this regular procedures failed to install, the DM said no available updates for my device. All the trouble happened after I installed the Desktop Manager 6.1 (or BB DS). my next step is to install the OS directly from Apploader.exe, and still no luck.
Then I tried to look at the vendor.xml file, its already deleted. Apparently there are two vendor.xml files which located in two different folders.
1. it is located in regular place C: > Program Files > Common Files > Research In Motion > AppLoader
2. the second vendor.xml file is located in user app data in this path C:\Users\Username\AppData\Roaming\Research In Motion\BlackBerry\Loader XMLWhat you need to do is deleting those two files and run the apploader, After deleting those two files, then run the Loader.exe. It should launch the program and you can upgrade the OS of your device.
latest update: This tricks also work on BB DS (DM) after restarting the device