Still having the same problem here. I narrowed it down to the config.xml file - deleting that fixed it so that I could save again.
Notepad++ v7 (32-bit)
Build time : Sep 21 2016 - 22:00:56
Path : C:\Program Files (x86)\Notepad++\notepad++.exe
Admin mode : ON
Local Conf mode : OFF
OS : Windows 7
Plugins : ComparePlugin.dll EmmetNPP.dll HTMLTag_unicode.dll JSMinNPP.dll mimeTools.dll NppCalc.dll NppConverter.dll NppExport.dll NppMenuSearch.dll NppTaskList.dll NppTextFX.dll PluginManager.dll PoorMansTSqlFormatterNppPlugin.dll PythonScript.dll RunMe.dll sql.dll Tidy2.dll XMLTools.dll