I have problem with Viber on this build. There is a update shown in store and when I want to update it, every time finished with error. Now Viber doesn't work and I can't uninstall it.
WM10 tapatalk
Try to uninstall Viber and download it from Store, if that doesn't help restart your device and try again. I got the same install error, but after uninstall app and reinstall from Store it works fine. If you can't uninstall, try to hard reset phone, but use that as a last resort.
It's kind usual with TP builds, the new store app is still slow and buggy, it happens randomly with some apps from time to time, I have now 7 apps on the list that can't be updated/installed and if Viber is app you can't live without you should make hard reset without thinking twice, it is the only way to fix such issues...