I sent an email to several addresses, that I put in the "Bcc" field. Now I want to send another email to the same addresses. How can I do this? I tried "reply", but it replies only to me—I didn't find a "reply all" option. I tried copying&pasting but got strange errors about "unidentified addresses".
If you sent the email using a mail client (Outlook, Thunderbird, etc) then I believe you are out of luck as most of these strip out the BCC fields upon sending. If you sent it from the Gmail site, then you can recover the addresses.
To do so, go to the Sent folder and select the message, then click the dropdown arrow in the bcc: field location.
The popout window this provides will include all the addresses in the BCC field. You can copy these and then paste them into a new email to send to them again. Because you are copying from a "display" field, not truly an email field, you may unintentionally include extra characters or non-email words (display names, etc). When you paste into a new email, check to see which Gmail has recognized as true email addresses and remove or correct any that it is unable to recognize. This should prevent any further "unidentified addresses" errors.
Using Thunderbird, highlight and open the orig mail; go to File, Save As and pick a name, save as TEXT on the drop down. The mail and the BCC list will be available as an easy copy and paste for a new mail. This is not possible from the Thunderbird mail screen...BCCs are not selectable as a group and I had 145....
For Gmail users, go to the original sent email in your sent folder. Click on the 3 dots on right for other options. Click "see original email" and then a full screen version will appear, with no changes in the BCC addresses. Copy and paste to your new composed email. I sure could have used this information myself-lol-lots of annoying time spent trying to edit the addresses until I figured it out!