I open tools and then downloads. I am unable to open any of the files in the download screen
I open tools and then downloads. A screen pops up with files I have downloaded through Firefox. I right click on a file and the open option is not highlighted. When I click it the file will not open. This is a new problem as this feature has worked before.
Opaite Mbohovái (1)
If Open and Open Containing Folder in the right-click context menu in the Download Manager window are grayed then that means that the file is no longer in the original download location.
It is possible that your anti-virus software is corrupting the downloaded files or otherwise interfering with downloading files by Firefox.
Try to disable the real-time (live) scanning of files in your anti-virus software temporarily to see if that makes downloading work.
See "Disable virus scanning in Firefox preferences - Windows"