GoKawiilUser troubleshoots Synology-to-UniFi UNAS Pro 8 NAS migration with Robocopy
A longtime Synology NAS owner attempted to transfer files to a new Ubiquiti UniFi UNAS Pro 8 over a 10-gigabit network, expecting the SMB file copy to be routine. Windows Explorer failed partway through with file system limitation errors, prompting a switch to Robocopy, which stalled at 92% with error 665 on certain files, including one called '05 Wires.m4p'. The user traced part of the slowdown to Robocopy's restartable /Z mode, a feature they had relied on since 2007 but which now dramatically hurt transfer speed.