reg file read as follows: Windows Registry Editor Version URL' reg file, the mailto entry was present in my registry, and clicking on the mailto link on a webpage did open a blank Thunderbird email message, ready to be written and sent. Using the Regedit program available in Windows 7, I found that there was no such entry on my computer. Another Mozilla page pointed me to a registry location where there was supposed to be a mailto entry. That might have resolved it for me.īut I didn’t get that Mozilla page when I first searched, so instead I found another way that may be useful in some situations. To do that, I had to go into Tools > Options > Advanced icon (not Advanced tab) > General icon. The Mozilla page offered a reminder that I could set Thunderbird Portable to check whether it was the default email client. I got this error:Ĭould not perform this operation because the default mail client is not properly installed.Ī search indicated that there were only a few sources of information specific to the portable version of Thunderbird.

While browsing online, I clicked an email (i.e., mailto) link.

Mozilla thunderbird portable