asp.net mvc 3 - MySql with MVC3 gives an error when calling context.savechanges -

i'm trying mvc3 application use mysql database instead of sql server 2008. have created associated database , objects in mysql. , updated connection string in web.config file reference mysql.data.mysqlclient.

when run application , try login, getting error

store update, insert, or delete statement affected unexpected number of rows (0). entities may have been modified or deleted since entities loaded. refresh objectstatemanager entries. 

i have custom membershipprovider , within validation process have following

 using (mycontext context= new mycontext())  {       --some checks here       ---         if (verificationsucceeded)         {             user.passwordfailuressincelastsuccess = 0;         }         else         {             int failures = user.passwordfailuressincelastsuccess;             if (failures != -1)             {                 user.passwordfailuressincelastsuccess += 1;                 user.lastpasswordfailuredate = datetime.utcnow;             }         }         context.savechanges();  ----this falls on          -- other code here      } 

the above code works sql server 2008, falling on mysql. idea how can resolve please?

i not have triggers defined on underlying table btw. application mvc3 ef code first. thanks,

if else having issue, problem guid though. on this, add following connection string

old guids=true

so example, connection string looks now.

<add name="mydb" connectionstring="server=localhost; database=mydatabase; uid=user; pwd=mypass; old guids=true;" providername="mysql.data.mysqlclient" />