Hi JDevine,
I notice that the error message “EXC_CRASH (SIGABRT)” is shown. According to the error, this issue can be related to Exchange. Given this situation, please try the following steps to narrow down this issue:
1. Open Finder, locate the following folder, and then delete it:
Documents\Microsoft User Data\Microsoft Lync Data
2. Start Lync for Mac, and then sign in to Lync Online.
3. On the Lync for Mac menu, click Preferences, click Account, and then clear the Use Microsoft Exchange for managing personal information check box.
Note: You need to perform step 3 quickly after you sign in.
4. Check the results.
You can also create a new user account on the affected Mac to test the issue.
Thanks,
Mindy Pan