This is a known issue in Silk Performer 2011 which can occur when searching for windows (CitrixSearchWindow) while a window is being destroyed asynchronously by a previous action such as a button click.

The Citrix replay engine keeps a list of windows in memory.  When a window is created it gets added to this list, and likewise removed from the list when the window is destroyed.  A CitrixSearchWindow or CitrixSearchWindowById function traverses this list.

If the list gets manipulated, for example, a window gets removed from the list, while one of these Search functions traverses it simultaneously, you may encounter the situation where the list iterator has become invalid and the function accesses memory which has already been freed.

'SP83_HF9_Citrix' has been released to resolve this. With the fix in place, the list manipulation is detected and the search function is notified in order to restart iterating the list.