The Results pane has been cleared to conserve server resources.
The result set that appears in the Results pane is automatically cleared after being idle for a period of time. This empties the Results pane, discards unsaved changes, and frees the resources on the database server.
You can re-establish the result set by running the query or view again.
See Also
Reference
Do you want to prolong your work with the Results pane?
Other Resources
How to: Edit Rows in the Results Pane (Visual Database Tools)