I've had similar issues with messaging after a hard reset on Windows 10 mobile (thanks to the cluster**** that 14295 is). I reverted to 8.1, then up to 10586, but my messages never appeared. Today, due to other issues, I went back to 8,1 again, but this time restored a backup to get my apps and settings back (as much as possible). Messaging recovered all my texts until 11/19/2015 which was about the time I installed windows 10 mobile. I've since put the insider app back on and gone back to 10586 (production ring), but still haven't gotten any more recent messages back. I've turned on and off the 'sync messages' setting. Changed the time range to all three options, rebooted in between, but nothing is getting the messages back. This really sucks. I really am hating Microsoft right now. My 1520 was working perfectly until they pushed out that garbage 14295 to the slow ring and hosed my phone. Now I can't get my phone back to where it was before that forced update.