entity framework - Update-Database fails on production server -

i've enabled migrations asp.net mvc project. migrations work on localhost. following exception after deploying server:

unable update database match current model because there pending changes , automatic migration disabled. either write pending model changes code-based migration or enable automatic migration. set dbmigrationsconfiguration.automaticmigrationsenabled true enable automatic migration.
view stack trace

there no pending migrations, though. adding new migration creates empty up() & down()

what reason doesn't work on server? i've tried deleting migrations folder, re-enabling migrations, deleting database, , let ef afresh. tables created, end exception.

update:
thing noticed is, when delete migration folder not database, , enable migrations, adds configuration.cs file, when it's supposed add file (initialcreate.cs)

this happens when doing tow different query on same list of objects on same time without using .tolist

example :

you can create context , list of testobjects edit 1 of objects save changes

var objectslist = context.testobjects.where(x=>x.whatever=true) objectslist[0].whatever2="asd" context.savechanges() 

the above code pass compailer , fail while running, solve should below

    var objectslist = context.testobjects.where(x=>x.whatever=true).tolist()     objectslist[0].whatever2="asd"     context.savechanges()