Issue: You are about to go over your storage limit in Salesforce.You noticed that the majority of the data that is using your storage is Salesforce tasks that were created by Marketo.
Reason: The reason for the huge number of tasks in Salesforce created by Marketo is usually because you enabled the functionality to have Marketo create activities to Salesforce. You can check to see if this setting is on in Marketo by going to Admin > Salesforce > Edit Sync Options. You will see the following:
Solution:
1. The first step you can take to stop Marketo from creating the tasks in Salesforce will be to uncheck the checkboxes in the above screenshot for the items that you no longer want Marketo to sync to Salesforce.
2. Once this is done, you will need to investigate solutions from the Salesforce side to delete the tasks in Salesforce that Marketo previously created.
Two of the most popular ways to delete tasks in Salesforce are: