What steps will reproduce the problem?
1. Login since 7.1

What version of the product are you using?
1.5.1

Do you have an error log of what happened?

Date: 2016-10-26 03:24:43
ID: 1
Error occured in: Global
Count: 1
Message: ..\AddOns\Chatter\Modules\Buttons.lua line 99:
   attempt to index global 'FriendsMicroButton' (a nil value)
Debug:
   Chatter\Modules\Buttons.lua:99
      Chatter\Modules\Buttons.lua:96
   (tail call): ?
   [C]: ?
   [string "safecall Dispatcher[1]"]:9:
      [string "safecall Dispatcher[1]"]:5
   (tail call): ?
   ...ce\AddOns\Chatter\Libs\AceAddon-3.0\AceAddon-3.0.lua:558
      ...ce\AddOns\Chatter\Libs\AceAddon-3.0\AceAddon-3.0.lua:551
   (tail call): ?
   Chatter\Chatter.lua:249
      Chatter\Chatter.lua:242
   (tail call): ?
   [C]: ?
   [string "safecall Dispatcher[1]"]:9:
      [string "safecall Dispatcher[1]"]:5
   (tail call): ?
   ...ce\AddOns\Chatter\Libs\AceAddon-3.0\AceAddon-3.0.lua:558 EnableAddon()
   ...ce\AddOns\Chatter\Libs\AceAddon-3.0\AceAddon-3.0.lua:651
      ...ce\AddOns\Chatter\Libs\AceAddon-3.0\AceAddon-3.0.lua:636
   [C]: LoadAddOn()
   ..\FrameXML\UIParent.lua:407 UIParentLoadAddOn()
   ..\FrameXML\UIParent.lua:498 TimeManager_LoadUI()
   ..\FrameXML\UIParent.lua:1010
      ..\FrameXML\UIParent.lua:907

Please provide any additional information below.

I think it's because they've added the Quick Join button for Bnet friends, that's just instinct though as I'm no expert.