Sorry, Firefox doesn't have a backup mechanism for allowed sites data. If you have a backup of your Profile, the file which contains that data can be replaced with the backed up version..

I am not worried about the allowed. Only the blocked. Do you know where it is in the profile? I can restore it from my working PC.

Thanks!

The purpose of the popup blocker is to block, not allow. If you checked that checkbox, you are blocking popups by default.

I found the file: permission.sqlite. Thanks!

That is right. I accidentally wiped out my block list and was able to restore the permissions.sqlite from the working PC. Thanks

You can try to restore a previous version of the permissions.sqlite database file that stores such exceptions

Right click: Properties > Previous Versions

• http://windows.microsoft.com/en-US/windows7/Previous-versions-of-files-frequently-asked-questions

Earlier I copied it from my old computer.

Thanks