When you save the configuration for folder or Workflow portlets, you may encounter one of the following errors:
Operation is not valid due to the current status of the object.
These errors typically occur if the folder or Workflow portlet configuration dialog box contains a very large number of folders or queues.
As a best practice, if your system has a very large number of folders and queues, perform portlet configuration using an account with privileges to fewer folders or queues. Doing so should prevent the errors and also make it easier to find the folders or queues you want to display in the portlet.
If using a different user account is not an option, then increase the aspnet:MaxJsonDeserializerMembers setting in the Web Server's Web.config file.
If you are configuring a folder portlet, ensure the setting's value exceeds the total number of folders in your system.
If you are configuring a Workflow portlet, ensure the setting's value exceeds the total number of Workflow life cycles and queues in your system.
If you expect your folder or Workflow solution to continue to grow, then you may need to increase the value further to accommodate the expected growth.