I had used the desktop app with success in the past on a Windows 7 PC. Recently got a Windows 10 and reinstalled the app (v 188.8.131.52), entered validation code. It doesn't sync up any texting history even if I select Sync. It DOES sync the contacts I have on my phone. Since it wasn't syncing texting history, I search on VZ help. It directed me to install the app via the Play Store. This app is worse than the desktop app!! It continually insists on syncing WITH MY DESKTOP CONTACTS! It makes no attempt to sync with my phone contacts!! The contacts on my desktop have no relevance to the contacts on my phone, so I do NOT want to sync with my desktop contacts.
And then in attempting to sync texting history, it only found 2 threads and only displayed a couple of messages.
Did you install the application from the Windows Store or the Play Store?
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.