This should work. It hasn't been marked as incompatible. We don't have a way to check for sure. Maybe you can tell us. :)

Thanks. Is this (MD5 Reborned Hasher) the only MD5 Checksum checker extension (add-on) to work with Firefox 11.0 on Windows 7 Ultimate x64? If no, would you please kindly introduce the other one(s)? Thanks in advance for your valued comments. Best, Danesh

Hi Danesh, It may be the only one. This forum is focused on Firefox help. We don't have the ability to get new add-ons made. They are built by community members. More info here - https://addons.mozilla.org/en-US/firefox/about

Thanks anyway