I tried restoring a fairly sizeable VM and I didn't see any errors stating that the restore process failed but when I tried to power on the VM I got an error message stating files were missing.
My question is: is there any way to tell what occurred? The event log doesn't really say and I didn't get an error in vCenter either.
You could check the detailed logs found in the Pure installation folder (e.g. /usr/local/pure/vmsn/log). The current log file is 'vmsn.log', followed by the 'vmsn.log.000', 'vmsn.log.001' and so forth.
However, I do not completely understand who gives you the error message that files are missing. Does it come from your vCenter/ESXi? What exactly does the message say and is there more info in vSphere logs? Does it prevent the VM from powering on or does the problem come from the guest OS stating it is missing some files?