Not working anymore in version 2.5.8. on FF 60.0.2.

I really like this extension but for a while now it's not working on my home computer, even if I uninstall and reinstall it. The sidebar opens when I click the Brief button in the toolbar but no feeds show up and clicking on anything (like options, refresh, etc.) does nothing. This is version 2.5.8. Works fine on my work computer, so not sure what the deal is.

Update 7/3: This is really messed up but to get Brief to work again I had to go into my Firefox roaming profile and delete all the websites in the "default" folder in the "storage" folder under the profile.

Feed Update problem solved: In my case "CCleaner programme" which I run daily erases "permissions.sqlite" file. Once I add this file to the exclude list, everything works fine.

Wow, finally an rss addon that suits me!!! Almost the same as Sage and Sage++ !!!
Here're some suggestions:
Please, can you please put like Sage(++) did, on the left pane, divide that space in two and at half below put a list of all feed articles titles from the feed that we are reading?! It would be much better than we scroll all the articles in the right pane!!
One more thing, can you please add firefox sync to the addon options and feeds?!
Thkx in advance.

Great extension, thanks ! The only one who succeeded in making me forget Sage (RIP).
I'll put 5 stars when you will add a button to push an article in pocket list ;-)
What do you think ?

Long time user for this extension and i'm happy that its upgraded to support FF57 ! , one issue that it seem "clear all items" button in the option not working .

Hello.
Maybe this is a bug, maybe i'm only too dumb for it. ^^

If i delete feed messages how can i get it back? Delete the whole feed and re-add does not help. Uninstall/reinstall brief - does not help.
The trash is empty.

I hope you can help me (or fix this issue).

Thanks

EDIT:
Thanks for your answer. Can you please give me infos for the hard way? I also try a diff. (files), but not found where the changes are made.

EDIT2:
Its fixed. :) You only have to wait until new feeds are coming and he will load the old ones again. :)

Hello I like your add on very much but now I have a problem
I need to transfer the opml file to another computer. each time I try Brief tells me that this is not possible because of (invalid file format. the xml file isn't well formed). Please help

Thank you for your reply. Now I have another issue. when I check "oldest first" nothing happens. Is there a workaround to fix this.