Getting "cannot complete because of unknown error" when using spot healing brush

[#1]

I am getting a random "cannot complete because of unknown error" message when using the spot healing brush.  I can move away from the area where the messge occurred and the tool will resume working, but will randomly show again with another area.  Any fix greatly appreciated!

[#2]

I am getting a random "cannot complete because of unknown error" message when using the spot healing brush.  I can move away from the area where the messge occurred and the tool will resume working, but will randomly show again with another area.  Any fix greatly appreciated!