In Google MailGmail, there are a few helpful tricks for knowing ways to know whether or not you have responded to an email. Learn more about conversation view Your options will depend on whether or not you are using Conversation View – You can learn more about this feature on Google’s support site.
Should you use Conversation View? It’s up to you! Feel free to test the feature out, and decide whether it’s a good fit for your workflow.
With Conversation View
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On
Navigate to mail.gmail.com and take a look at your inbox. If you have already replied to the a message, a number should appear in the sender field you will see to the right of the original sender's name followed by "me" and (2)sender’s name.
In this example, I received a message from Dennis and then replied, and the Dennis, me (2) shows that I did in fact reply:
the example below, John sent me an email, which I have replied to. The number to the right of John’s name corresponds to the total number of emails in the thread.
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With Conversation View
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Off
From the inbox, hold your mouse over a sender's name (but don't click).
In the address card that appears,
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select Open Detailed View.
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The resulting screen will show
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Remember, you can always try both conversation view on and conversation view off to see what works best for you: Learn moreyour open threads with that user, as well as recent calendar events and shared documents. This should include your replies to the user, as well. Click on a given message to view the full thread.
Alternatively, you can run a search of your mailbox using the following structure: "from:me to:INSERTEMAILHERE".