The first thing that I do after starting my Windows PC is checking my e-mail messages using the Mozilla Thunderbird e-mail client. I have been using Thunderbird for some time now and am very satisfied by its performance. It offers more security features than any other email client for Windows or for Linux. As of late, I started to see a thin gray line near the clock on the Windows desktop after using Thunderbird. This line won’t go away until I restart Windows. After getting annoyed for 2-3 days, I began to investigate and found out that it was due to Mozilla Thunderbird alert popup notification. Apparently, the notification alert never closes down completely and keeps running in the background (for version 38.0.8 of Thunderbird e-mail client).
To avoid such annoying lines appearing on your screen, you can kill the thunderbird.exe process after using the Thunderbird client or just disable the new message alert notification in Thunderbird. Here is how:
- Open Mozilla Thunderbird and click on the hamburger icon (looks like three horizontal lines) near the top-right corner of the window.
- From the menu that shows up, select Options → Options. This will open the Thunderbird options window.
- In the options window, select the General tab, if it is not already selected.
- Uncheck the checkbox labeled Show an alert under the category When a new message arrives.
- Click the OK button to save the settings.
From now on you will not see the alert notification popup whenever you receive a new email message in any of the configured email accounts in Thunderbird. But you can still see the Thunderbird icon in the notification area and listen to the new message alert sound. For many people this is enough and you can always check the new messages by opening the main Thunderbird window itself.