You will need to delete keys and strings from Windows registry to remove Acronis SnapAPI drivers
Windows NT 4.0
Windows 2000, Windows XP, Windows 2003, Windows Vista, Windows 2008, Windows 7
(!) In Acronis True Image Home 2010 Build 6053 or higher, Acronis True Image Home 2011, or Acronis Backup & Recovery 10 Build 11345 or higher snapman is also in the LowerFilters
(!) If snapman string is not present in a given subkey, just skip to the next key.
(!) If you are using an NT-based Windows operating system (Windows NT 4.0 and higher), do not delete the driver files (SnapAPI.dll, Snapman.sys) manually from the disk (as opposed to removing them from the registry). This will make the system unbootable even with the "Last Known Good Configuration" option.