Well, you could right-click on the shortcut to Thunderbird and look at the Properties to see where the executable is in the Target field. The default place in Windows when using the 64bit version is: "C:\Program Files\Mozilla Thunderbird\thunderbird.exe".

If you have the 32bit version installed, then it would be in the "C:\Program Files (x86)" directory instead.

The Thunderbird shortcut is on the Taskbar and does not have any Properties There are no Thunderbird files in either Program Files or Program Files (x86) The only Thunderbird.exe file is stored in C:\Users\USER\AppData\Local\Microsoft\WindowsApps\MozillaThunderbird.MZLA_h5892qc0xkpca 0 bytes SurfShack does not recognize this file as a valid application to Bypass

What you have done is install thunderbird from Microsoft site. That version works but has incompatibilities and the troubleshooting features don't work. If possible, I encourage you to uninstall it and install from https://www.thunderbird.net/en-US/thunderbird/all/