After reading the manufacturer’s suggestions to solve the given scenario, I checked them all out (and if you have the same problem, you should too):
- This issue can occur if you have not installed the latest updates.
- Outlook may be in use by another process.
- A previously installed add-in may be interfering with Outlook.
- Your mailbox may be too large.
- You may need to repair your Office programs.
- Outlook data files may have become corrupt, or damaged.
- Antivirus software may be outdated, or conflicting with Outlook.
- Your user profile may have become corrupt.
- Another program may be conflicting with Outlook.
After going through all of that unfruitful effort, I noticed that the program only crashed when replying to digitally signed messages. With that piece of information I arrived at this support article:
Application freezes when you access a password protected certificate in Windows 8
I requested the hotfix, downloaded it and restarted the PC. I took one of the messages that caused the crash and then, instead of crashing, the following window appears:
This is because I also have a digital certificate installed and Outlook tries to reply in the same fashion as the sender.
Hope this helps someone.