You may be experiencing any of these issues:
An issue was discovered in HTC Sense Home version v7.50.737501 that would cause HTC Sense Home to crash periodically when returning to the home screen. This affects HTC phones upgraded from Android 5.0 (Lollipop) to Android 6.0 (Marshmallow). Phones that featured Android 6.0 natively are not affected. The most commonly affected phones are:
Ensure the phone is fully updated, by following these steps:
Follow these steps to perform the Clear Data function on the HTC Sense Home application: