iPhone 6 with ios8. After months of normal operation, suddenly now I cannot delete either a single text or an entire conversation. When I try, the message or conversation appears to be gone, but the app then freezes and I cannot access any other text conversation. Eventually I get a blank text screen as though there are no conversations at all. After a power off/power on, all conversations are back, including those which I deleted. I have scoured the web for a solution and tried the various suggested remedies. Nothing works. Has anyone else encountered this issue and found a solution?