It seems to be something in Windows that changed. I wasn't entirely sure at first last week but the timing seem too coincidental. Now there was another update and apparently xEdit works again. Wrye Bash seemed to start loading and recreated a blank bash file but then crashed afterward. I don't know if this is a problem with other Windows versions though.
I'm having the same issue. Wrye bash and Loot doesn't load. I also tried loading both fo4edit and tesvedit but apparently they aren't showing any plugins. What Windows version are you running by the way?