Yes I know this problem has been reported many times, but my case doesn't seem to fit any proposed solutions (unless I miss something).

The ASP.NET page setup (simplified) is: user clicks a link (technically a node of Infragistics WebDataTree) and this action binds a grid (Infragistics WebHierarchicalDataGrid) located in an UpdatePanel.

Now this works fine in a local test system. When deployed to a production server - it also works - most of the times, but sometimes this throws error:

Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request


This seems to happen more if the production system under heavier load (more users accessing it). Again, I am not building any dynamic controls, just a button and a grid that is populated on button click.

What could be causing this? Why this doesn't happen always, but sometimes? Any idea how to fix it?

UPDATE

Here's confirmed scenario

  1. If one user accesses and uses the page - error doesn't happen
  2. If two user doing the same (can even be 2 browser sessions from the same client) - error happens.



How could one session affect viewstate of another?