Originally Posted by CO_BBTechie
This is indiscriminate and will remove ALL SMS messages. But it will remove the messages without having to wipe.
There's a common and similar issue with email messages that cannot be deleted. You might want to try one of the solutions for the email problem. It's basically the same thing but you perform a selective backup, wipe the database (email or SMS) on the BB, and then perform a selective restore. After the restore delete the messages that could not be deleted.
I have no idea if this will resolve your undeleteable SMS issue but it seems to work for the undeleteable email messages.
- From the BB tech knowledgebase at Blackberry.com which can also be a handy resource.