I have had many leads that were unable to sync with the following error message: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY: ContactPrimaryFlag: System.LimitException: Too many SOQL queries: 101 I suspect this is an issue with Salesforce and I believe the issue is the high number of workflows and validation rules we have in our Salesforce instance. I had the same problem using Data Loader and the solution was to change the batch size in the Data Loader settings. This resulted in a slower process, but no issues with too many SOQL queries. I have not been able to figure out how to limit the batch size for Salesforce sync.
Has anyone had the same issue regarding the Lead sync from Marketo to Salesforce? Does anyone have a solution?