Salesforce - NetSuite Connector Error: JSON String Exceeds Heap Size Limit

Error

JSON string exceeds heap size limit 
Error is in expression '{!startOpportunitySync}' in page netsuite_conn:opportunity_sync: (System Code)

This error is due to the limitation on upload files in NetSuite and may occur if the file attached to the Opportunity record exceeds 5MB.  If the file is larger than 5MB, remove the file from the record and then add it back to Salesforce and NetSuite after the sync is complete.