The original issue of the original thread, is exactly like my issue here, and was stated as follows:
bookbear wrote:I have a problem with UNinstalling Light... it simply will NOT uninstall, keeps giving an error message saying that the uninstaller is not valid. The original installation files were downloaded from SourceForge directly. I am running Win10, no viruses or malware, and everything else is functioning properly. I can't even copy and paste the error message, but it starts with "Installer Integrity Check Has Failed."
I had originally replied to that post in the original thread, indicating I was having the same problem, and inquiring about any solutions to said problem. My inquiry never saw the light of day over there, so hopefully it will here.
Thanks in advance for any advice on how to uninstall Firefox Light!