I created a time based workflow rule that will go out to any LEAD that is in PROSPECTING stage after 2, 5, 7, 10, 14, 30 days. The idea is an email will go out to a prospect who is in the LEAD PROSPECTING stage until the lead is converted to an Opportunity - doesn't matter if there is activity on the record or not. Problem is when a rep tries to convert the LEAD to an OPPORTUNITY, they get an error message that says" Cannot convert because record is used in workflow". I then have to go in and delete that record from the workflow queue.

Evaluation criteria is:

Only when a record is created

How can I stop this from happening? I plan on creating additional rules for each stage of our sales process that will trigger emails at the same time intervals and it won't work if this continues to happen.