While in Windows, CPU usage and/or disk access is constantly higher than it should be. For example, the CPU may run around 50% and the drive around 45% indefinitely, even when the computer is idle. Depending on the system configuration, the problem may only appear under certain circumstances (e.g. when a partition is hidden).
This can be caused by the Acronis snapman driver, which is installed with True Image and Disk Director, as well as the free Western Digital and Seagate (DiscWizard) versions of True Image.
If the Acronis software is no longer needed or being used, the best option is to uninstall it. Otherwise, check for an updated version of the program being used and try it.