I have a workflow with Set Field Value action to uncheck the To Be Emailed box on the Credit Memo Before Record Load. It isn't working. There are no conditions. Set to apply On Create. This is for Credit Memos to be created from Invoice or RMA.

It might need to be on After Field Sourcing, because when the customer data sources in, it's likely overriding that box with the customer's preference (which may be to check it)

I tried that already but that doesn:t work if I create the CM from an Invoice or RMA because I do not have to select the customer. After Field Sourcing does not occur.

Right, that makes sense. Hmm

It worked when I used Before Record Submit.

Interesting. Glad you got it working