Outlook freezes on reply with "Starting Word as your email editor"

If you run into this problem when replying or forwarding messages, it's most likely because Word is still running in the background because of some issue you had earlier. You can either open your task manager and look under the processes tab for "winword.exe", or you can use the Outlook email editor instead. If you choose to look in the task manager and happen to find one or more winword.exe processes running, you'll want to end each of them. In order to make it simpler on yourself, make sure you don't have Word or any email messages open, as each of them will register a winword.exe process. You're only looking to close the background processes that shouldn't still be running, which is why you should close any others that may create a false background process.

If you'd rather not mess with using Word, in Outlook, go to Tools->Options->Mail Format, and uncheck the box that says "Use Microsoft Word as the default email editor". This will default your email editor to Outlook's built-in editor. However, you do lose a lot of different features when you do this, so you may not want to use this options. You can try it, and if at any point you'd rather got back to Word, simply go back in and check that box again.