Question
Within Legacy Unison Light Manager, I see a dialog appear titled "P80" with the text "The Win 16 Subsystem has insufficient resources to continue running. Click on OK, close your applications, and restart your machine." This error might occur frequently, and cause the software to exit.
Answer
This problem is a Microsoft bug that has never been fixed. The Graphic Device Interface (GDI) allocates handle numbers sequentially, and it prefers to reuse a freed handle rather than allocate an unused higher handle. If the GDI handle count exceed 16384 during the current session, this error occurs.
Note:
You are probably using session 0 (the same that displays the logon screen when you start you computer), so the only way to reset the session is to reboot your computer. You don't need to close out all applications, as they will usually close when the computer is rebooted.
The only way to solve this problem is to reboot your computer!