This option has been disabled for system disks or partitions on system disks
As a workaround, recover from Acronis Bootable Media
You either have 1) Windows Server 2008 R2, or 2) Windows Small Business Server 2011, or 3) EFI system partition, or 4) EISA service partition
The following Acronis products support EFI-based systems:
This article describes how to change the delay time and key for starting Acronis Startup Recovery Manager.