Clear layer comp warnings
Certain actions create a state where the layer
comp can no longer be fully restored. This happens when you delete
a layer, merge a layer, convert a layer to a background, or convert
a color mode. In such instances, a caution icon 
appears
next to the layer comp name.
Do
one of the following:-
Ignore the warning, which may result in the loss of one or more layers. Other saved parameters may be preserved.
-
Update the comp, which results in the loss of the previously captured parameters, but brings the comp up to date.
-
Click the caution icon to see the message explaining that the layer comp can’t be restored properly. Choose Clear to remove the alert icon and leave the remaining layers unchanged.
-
Right-click (Windows) or Control-click (Mac OS) the caution icon to see the pop‑up menu that lets you choose either the Clear Layer Comp Warning or the Clear All Layer Comp Warnings command.