Error -18 ?

[JimCollinson]

Previously i'd been rendering out webp alongside jpg and png without issue (hacky, but it worked) but now i've started to bump into this error. From the log:

[debug:generator-assets 10:15:03.363 assetmanager.js:560:22] handleChange: { metaDataOnly: true,
  selection: { previous: { '5': [Object] } },
  id: 195,
  timeStamp: 1506676503.347,
  count: 3 }
[info:generator-assets 10:16:17.605 assetmanager.js:442:34] Render complete: 530-3Q-Pair-x150.jpg
[info:generator-assets 10:16:17.609 rendermanager.js:178:26] Rendering: 530-3Q-Pair-x1600.jpg (13;8)
[warning:generator-assets 10:16:17.618 filemanager.js:215:30] Unable to rename asset; copying instead: { [Error: EXDEV: cross-device link not permitted, rename '/var/folders/lm/qn_w382j61z8vlf13fkmm60m0000gn/T/tmp-4554uuGPQsahH6Yp' -> '/Volumes/Design Assets/Product Shots/Product Shots/Speakers/Series 5/530 Pair Hi-Res 2-assets/530-3Q-Pair-x150.jpg']
  errno: -18,
  code: 'EXDEV',
  syscall: 'rename',
  path: '/var/folders/lm/qn_w382j61z8vlf13fkmm60m0000gn/T/tmp-4554uuGPQsahH6Yp',
  dest: '/Volumes/Design Assets/Product Shots/Product Shots/Speakers/Series 5/530 Pair Hi-Res 2-assets/530-3Q-Pair-x150.jpg' }
[info:core 10:17:34.081 photoshop.js:475:26] 22ms to receive 600.4 kB (27289.6 kB/s)

Dunno what the deal is, or if it relates to webp, but if I remove the +webp85% from the layer name it renders out the slowly, but successfully.

[iabukai]

It seems a kind of permission issue caused by fs or fs-extra npm lib.
But actually it's "just" a warning so at the end the file will be copied into your target folder.