View state maintains data in a page across postbacks. And this data passes in form of hidden field data. There is a certain limitation of this hidden field. If your hidden field will be greater than that specified value, then sometimes firewalls and proxy servers refuse to let your data passes through. And in that case you have to disable your view state .This might cause many problem if you want your data to be passed.
So to overcome this problem you can do viewstate chunking. This is a process of splitting the data into multiple chunks and putting them into multiple hidden fields, So that there will not be any problem to your data to pass through. This chunking is done by adding “MaxPageStateFieldLength” property in the page tag in web.config file. The default value is -1 which indicates there is no maximum limit of data. You have to give the integer value which indicates the maximum bytes size for a viewstate field.
<pages maxPageStateFieldLength=”20″ >
After verifying the amount of data you may prefer to do viewstate chunking.