1. Create a folder compare session with beyond compare like the following:
  2. Save the session with a file name without any special characters (e.g. < or >) or spaces (i.e. necessary not to confuse the scheduler).
  3. Save the following beyond compare script to right-updater.bc file. 
    #Write to right-updater.log
log normal "right-updater.log"

#Load a folder compare session.
load "%1"

#Confirmation will be set to yes by default. 
option confirm:yes-to-all

#Make the right equals to the left of the loaded folder from the session.
sync mirror:left->right
  4. Save the following powershell script to bcrunner.ps1 file along the side right-updater.bc file. 
    #expects 2 command line parameters
param([string]$script, [string]$session)

#The beyond compare command to be used.
$cmd="C:\Program Files\Beyond Compare 4\BComp.com"

#Holds the session argument for the beyond compare command.
$args="""$session"""

#Write on screen the actual command to be executed.
write-output "$cmd /silent @$script $args"

#Perform the command.
&$cmd /silent @$script $args
  5. Schedule using windows task scheduler and on the actions tab fill in the following fields like:
    Action Start a program
    Program/script powershell
    Add arguments(optional) ./bcrunner.ps1 right-updater.bc <SAVED_SESSION_FROM_STEP_2>
    Start in (optional) <DIRECTORY_OF_BCRUNNER.PS1_FILE_FROM_STEP_4>

    Note: Fill-in the other tabs of the scheduler accordingly.