MS Outlook and Word crashes opening HTML content (KB3097877)
This morning multiple users started complaining that their Microsoft Outlook was crashing when trying to create a new email. Replies and forwards were not affected.
After some troubleshooting, involving Outlook safe mode, disabling add-ins, creating new profiles, etc. I found that the issue was caused by custom Outlook Themes that were used as templates for new emails. These themes were basic HTML files, saved in C:\Program Files (x86)\Common Files\microsoft shared\Stationery. There was nothing fancy in them, just few tables, some text, images and few links.