Acronis True Image 2016: Update to Build 6571 Fails with "Access is denied"

Symptoms

1. You have Acronis True Image 2016 installed and update it to build 6571.
2. Installation fails with error "Access is denied".

Solution 1

1. Open the installation log (see this article, if you need help finding the installation log).
2. Search for this message:
   MsiFileTrackerInstall64_file_tracker_api__I returned actual error code 1603