I use Pale Moon 3.6.8 as my default browser on my desktop computer and I'm loving it.
More about Pale Moon here
I installed it a short time afterward, uninstalled Firefox. I'm now facing an issue that whenever I open a link from an external application, e.g. MS Outlook, I get an error message similar to this one. However, the URL still opens with no problem.
There was a problem sending the command to the program
I have searched and found this
solution. Scroll down to the bottom of the page. I have deleted the said registry keys and yet no luck. I'm still getting the same error message each and every time.
Edit- Solved through updating to the latest version.