Adobe have released a security update for Acrobat (hardly a rare occurrence). So, being the security conscious user that I am, I went ahead and updated. Now Acrobat Reader wants me to restart my system.
Why? This is October 2016, not the 20th century. User space applications should not require a restart of the system. Firefox doesn't require a restart every time it updates. Chrome doesn't require a restart every time it updates. Even Wireshark doesn't require a restart.
It's just not good enough Adobe.