The tooltip shows the name of the shortcut that was pinned to the taskbar. You can go to Control Panel and look at the list of installed programs and check if more than one installation of Thunderbird is listed. You can also open Task Manager, switch to the Details tab and see if there are multiple instances of Thunderbird running.

The tooltip shows the name of the shortcut that was pinned to the taskbar. You can go to Control Panel and look at the list of installed programs and check if more than one installation of Thunderbird is listed. You can also open Task Manager, switch to the Details tab and see if there are multiple instances of Thunderbird running.

Thanks Stan but only one installation found and no Thunderbird running in Details.

Then you don't have multiple Tbird running. You could try a clean reinstallation of Thunderbird and see if it fixes the issue. However, it's possible it's something else affecting the responsiveness of your system and not Thunderbird's fault. To clean-install Tbird, uninstall it via Control Panel, then open C:\Program Files (x86) and delete the Thunderbird folder found there. Do the same for the one in C:\Program Files if it exists. Next, download and install Thunderbird from www.thunderbird.net. This will not affect your Tbird data or profile, so you won't lose anything.

That is certainly a solution but it would be my last resort. I've had this problem before, a few months ago... I have 'background service for updates' turned on so it might be a Thunderbird process? I'll wait a while before reinstalling.

Sometimes updates don't go as smoothly as expected, so a clean install is the shorter path to getting it done. Also note that a clean install is not necessarily a solution because there could be other external factors affecting Tbird's performance, for example overzealous security programs like antivirus. Keep us posted of the outcome when you finally decide to do it.

Another probable cause is an incompatible/buggy/outdated add-on if you have any installed.

Yes there were other factors, 6 Firefox background processes running. When I fix it or when it fixes itself, I'll let you know.

Just a thought, simple and not 100% sure, but anyway: maybe the icon Thunderbird(2) means you have two shortcuts in same folder, target to execute Thunderbird.exe. So, in taskbar I would right click the TH(2) icon, then again right click on the TH(2) icon in smaller window, click on Properties, and check Start in: folder location for shortcuts.

I told you what the tooltip displays. Leave the start in location alone. What is the name of the shortcut that you pinned? Rename it, then unpin and pin it afresh.

Yes, that was it. Somehow I had pinned Thunderbird to the taskbar twice! I have no idea how that happened but problem solved. Thanks