I found this when logging in this morning:
And some related events in the System event log:
Log Name: System Source: Microsoft-Windows-DiskDiagnostic Date: 26/08/2015 9:20:08 AM Event ID: 1 Task Category: None Level: Critical Keywords: User: SYSTEM Computer: ***** Description: Windows Disk Diagnostic detected a S.M.A.R.T. fault on disk ST500DM002-1BD142 (volumes D:\). This disk might fail; back up your computer now. All data on the hard disk, including files, documents, pictures, programs, and settings might be lost if your hard disk fails. To determine if the hard disk needs to be repaired or replaced, contact the manufacturer of your computer. If you can’t back up (for example, you have no CDs or other backup media), you should shut down your computer and restart when you have backup media available. In the meantime, do not save any critical files to this disk.
Log Name: System Source: disk Date: 26/08/2015 9:20:07 AM Event ID: 52 Task Category: None Level: Warning Keywords: Classic User: N/A Computer: ***** Description: The driver has detected that device \Device\Harddisk0\DR0 has predicted that it will fail. Immediately back up your data and replace your hard disk drive. A failure may be imminent.
Log Name: System Source: iaStorA Date: 26/08/2015 9:04:54 AM Event ID: 4102 Task Category: None Level: Error Keywords: Classic User: N/A Computer: ***** Description: Error log: Smart event occured on disk :S2AXWXVT
Fortunately, this is my D: drive. There’s only a couple of virtual machines there, but nothing I can’t recreate if necessary. That’s the first time I’ve seen hard disk SMART diagnostics kick in like that.