In MES 5.1.0 and later you may find the need to perform a full sync, but don't want to sync all of the files.  

This can be accomplished through the System Administration on the Classic Portal using the ERP Configuration > ERP to MES Synchronization Entities

Uncheck the items you don't want to sync. Example: uncheck everything but the entities highlighted in yellow above and click Save at the bottom of the page. 

Then run the Sync All Under the ERP to MES Full Syncronization.  The above screen shot can be used to set the sync all back to the default, but it is recommended to take a screen shot of your current settings to allow you to set your sync back as it was on your system.