Javsay

Also, figured out that you can only reflink to the exact same folder. So in the case of @Nem, if he had done the above, to not get the error he got, he would need to have done: cp --reflink /mnt/cache/VM/UbuntuBase/vdisk1.img /mnt/cache/VM/UbuntuBase/disk1.img You can then copy the image to another folder however you cannot reflink from e.g. UbuntuBase to UbuntuNew, it has to the same folder it appears.

Figured out the soloution. Two things seem to create the problem you mentioned about invalid argument and 0KB. 1. If COW (Copy on Write) settings are disabled then this happens - this setting is in the share settings and you have to set it to "Auto" instead of "disabled" when creating the share 2. If you create your VM disk folders through the network/SAMBA I.e. You access it from my network places and you create subdirectories via that in Windows then try to cf reflink to there. The way around this is is, go to your VM, create a vdisk through the settings panel in a new folder of your choice, going via usershares to navigate to the folder of your choice.. Then delete the vdisk1.img and use the standard instructions posted above and being aware of not doing from 1 disk to another or going via user shares. This seems to do the trick, I'm new to UNRAID but that worked for me. Hope it helps!