Check if Application Service reaches Windows Maximum Desktop Heap Limit

Go to Start, All Programs, Administrator Tools, Event Viewer.
Select Windows Logs, System.
Right-click Systems.
Select Filter Current Log.
Select the following Settings:
- Event level: = Warning
- Event Sources: Win32k (Win32k)
- Event IDs: 243
Select OK.

Filter the Current Log Window where you check the box for Warning. Then select Event Level of Warning and Event IDs 243.

NOTE: If you received a Desktop Heap failed warning message, review Can’t create a new session with many users' to help resolve the issue.

System Event log. A warning displays with a Warning "A desktop head allocation failed".