Acronis True Image 2015 clone disk stopped working after latest Windows 10 update

I have used Acronis software for years without any problems.  My Dell Optiplex 9020 (i7-4770) was originally Windows 7 Pro and was upgraded to Windows 10 Pro.  Acronis True Image 2015 worked with both of these versions.  Just recently, Windows 10 did a big update.  When I plugged in the clone disk (through direct SATA connection), at first, the machine did not recognize the clone disk.  After switching cables, I could boot off of the clone disk (with old Windows 10 Pro) but I could not clone from the main disk to the clone disk. No matter what I did, I could not boot off of the main disk (new Windows 10 Pro) while the clone disk (old Windows 10 Pro) was connected internally.

I ended up formatting the clone disk so the machine would boot off of the main disk (new Windows 10 Pro).  I run Acronis True Image 2015.  I start the clone process.  It starts off looking OK.  The machine reboots and, after a few minutes, it reboots again without having performed the clone.

Machine: Dell Optiplex 9020 (i7-4770)

(New) OS: Windows 10 Pro, OS Build 10586.14

Main Drive: Seagate 2TB

Clone Drive: Seagate 2TB