This is a Verizon HTC One M8 and Lync 2013 used to work fine on 4.4.4 before the Lollipop 5.0.1 upgrade.  Now, it immediately crashes on startup.  Are the errors being logged anywhere?  Any ideas on where to start with this?  I've already cleared app cache and reinstalled.

Hi,

It seems to be an known issue.

Here is a similar case for you. Several HTC M8 users reported that they met the issue with Lync 2013.

https://social.technet.microsoft.com/Forums/office/en-US/272f7d5c-f2f6-4596-8db1-263dcfc8434e/lync-mobile-app-will-not-launch-after-upgrade-to-lollipop-on-htc-one-m8?forum=ocsclients

You can feedback in the link below, hope it will be repaired soon.

http://blogs.technet.com/b/lync/archive/2012/11/01/lync-app-feedback-you-asked-and-here-it-is.aspx

Best Regards,
Eason Huang