Rated 4 out of 5 stars

There is a problem in the new version 0.13.4
I can't open any saved pages with the ext. ".MHT", even the old saved ones by previous versions or even the pages saved by internet explorer 6. it show a blank page named "untitled". The only pages I can open are those with ".HTM" extension.
I'm using Firefox 3.5.1, windows XP SP2.
Thanks..

This review is for a previous version of the add-on (0.13.4). 

It has been reported that, if the file extension is written in uppercase, Firefox fails to open the file. Renaming the file extension to lowercase can be a viable workaround until the problem is solved.

I'll mention this in the "known issues" section of the release notes for the next version.