visual studio - XAML Designer Failed to load -

i trying develop windows phone app , using visual studio 2013 update 4 development.

i using pivot app (windows phone) development.

my problem is, xaml designer failed load. did search on stackoverflow , google , found solutions , none of them worked.

the solutions tried far :

• repair of visual studio.
• clearing contents in c:\users\<user>\appdata\local\microsoft\visualstudio\12.0\designer\shadowcache (answered here on stackoverflow
• deleting componentmodelcache c:\users\<user>\appdata\local\microsoft\visualstudio\12.0

and none of these worked.

please me if have solution.