OK so I did another test and bcc'd three email addresses in the family so I can check they got them, which they did. In that sent email the 'details' button is there and still there a day later so I can click on it and see which emails I sent to. But in two emails I sent the day before the 'details' button was there for a few hours and then disappeared.
I am filing the sent emails in a folder... could this have something to do with it?
Or could it possibly have something to do with the fact that some addresses I am sending to might be gmail or yahoo email addresses or something like that?
I can try another test in Safe mode but that won't really show me much as the test I did within the family worked fine so it should also work in safe mode. I could send the email with about 20 bccs in it again but I am concerned the same thing will happen again and then I am no better off - plus the recipients will think I am bombarding them with emails if they did actually get the first one!
Sorry, I am not an expert by any means, I just run a small holiday business. I am just trying to send christmas wishes to our customers without having to send emails one by one... it shouldn't be this difficult should it?
I have been using apple products for ten years or more and there does seem to be odd things like this which happen and cause hours of frustration....