Yesterday, in celebration of the leaked BlackBerry Messenger 5.0, we discussed how to install BlackBerry Messenger. Within the article we linked to sources where you can download the application, both over the air and to your desktop. We also warned that you could encounter troubles. Practicing what I preach, I downloaded the 83xx version for OS 4.5 over the air. After a hefty file download, installation, and reboot, I saw that my BBM was gone completely. It seems to be a Verizon problem for those with OS 18.104.22.168. Even so, some people might not like the leaked messenger. After the jump we’ll go over what to do if you want to downgrade. Before you do anything, go back up your contacts using BlackBerry Desktop Software. If you have a Mac…sorry. I could be wrong (it happens), but I can’t find a way to backup Messenger contacts with PocketMac and do not have Missing Sync. If anyone wants to chime in, I’ll update teh post. Now that you’ve backed up your Messenger contacts, it’s time to say bye-bye to the application. Head into Options, Advanced Options, Applications, find BBM 5.0, and delete that sucker (see: how to delete BlackBerry applications). Now it’s time to reload. If you have BlackBerry Desktop Software, you can use the Application Loader to reinstall BlackBerry Messenger. Once you’re done with that, you can go to the Restore function and bring back your contacts. That should have you back up and running with the old software. For those who don’t have Desktop Software, you can download BBM over the air. Just head to http://yourcbcfamily.org/bb/curvebbm/ from your BlackBerry browser. Click the link, and you’ll be able to download and install the file. That’s what I did, and voila, BBM back and running — though with no contacts (so add me!). The caveat with the link, though, is that it’s designed for 22.214.171.124, so I’m not sure if it will work on other OSs. You can give it a try, of course, but remember that it might mess up your BlackBerry even more. I hope this helps. I was damn glad to find it after I spent a good while trying to figure out why BBM was not working on my Berry.