Once Desktop Manager is installed on the PC you can then install the OS versions to the PC as well. Simply download and install to the PC, then delete the vendor.xml file. For example, you purchase a new Pearl with 18.104.22.168. Then you see that a new update is available and you download and install 22.214.171.124 to your PC. You delete the vendor.xml and upgrade away. Then later you decide to downgrade back to 126.96.36.199. You simply go to Control Panel >Add Remove Programs and remove the 188.8.131.52 installation package. You then go to Desktop Manager and run Application Loader and.......nothing happens. What? You never had 184.108.40.206 installed to your PC. So now, you have no OS installed on the PC for loading to the BB. I hope this makes sense. HEre's what to do.
1. Make sure the latest version of Desktop Manager is installed.
2. Delete ALL other OS's from the PC under Control Panel, Add/Remove Programs
3. Download and install whichever OS you are wanting to downgrade the BB to.
4. Delete the vendor.xml file
5. Plug in BB, Run DM/App Loader.
The Apploader will sense that a "downgrade" is sensed.