To me it sounds like a temp issue, could it perhaps be dust in the cooling system or failing fan or bad bios settings for the fan?
Could also be a failing PSU.
When you after those shutdowns go into bios, does the bios say something in the log to the bottom right (I think if the watchdog fired then the bios should have a logentry about the event)?
Also does this only happen for your batch of NUC with the 2500 series SSD or do this also happen with other SSDs in the same system?
It does not seem to be a heat issue. System seems to think there is no hard drive installed when there is. Could be a bad batch of NUC's maybe. Have sold many that do not have this issue. First time we have had this problem and just seems weird that there are 3 at the same time! I was checking to see if this problem has happened with any one else and might have an idea of what the issue is. Can't check logs when system does not see the hard drive any more. We will do more testing.
And this happens for all vendors/models of SSDs you put into these failing boxes or just the 2500 SSD?
This is really a longshot but there have been revisions of the Intel NUCs during the year regarding SATA compatibility (to improve SATA port signal integrity / to increase drive strength) as described in:
From which revision are your boxes and could you perhaps find a different revision to see if the problem exist also at that revision?
MsSstewart, some recommendations that we can give you are the following:
Check if the NUC is running the latest BIOS version?
If it is using the latest one, please try rolling back to the previous BIOS version available.
In case the issue persisted and if the NUC is still under warranty, please get in touch with our Warranty team in order to replace it http://www.intel.com/p/en_US/support/contactsupport or submit a web ticket at the following URL