Error. Failed to grab still

Hello everybody.
I have a lot of problems grabbing still. sometimes it works but most times it don't.

I tried changing the directory where the stills are supposed to get saved but it still don't work.
Here is a screengrab of the error.
Please help. is making me crazy.

[Peter Chamberlain]

Do you have the same problem if you turn off render cache?
Peter

in my case, i cant grab still using shortcut command+option G. why??
but play still, next still can do

Up on this thread. I am getting the same problem. It appears that the issue comes up only on a clip which has grades on, I've tried with other ungraded clips, and it catches the still.
Tried everything, the stills path is correct, I've rebooted twice the system with vram clean up, I am running Resolve 11 on a late 2013 MacBook Pro 15".

Please any ideas?

I had the same problem finally figured it out. In my case it was the node(s) with denoise fx applied via the Motion Effects tab. If I turn off the node with the denoise then I'm able to grab the still. I'm working on a 27" imac 2013 computer which struggles to keep up with Davinci if I apply a lot of FXs. Really need to upgrade.