Software Update - invalid Apple cert warnings!

[MrElvey]

I am simply trying to check for any software updates and I get this error message.

An error has occurred
The certificate for this server is invalid. You might be connecting to a server that is pretending to be “swscan.apple.com” which could put your confidential information at risk.

I restarted Software Update/the App Store and didn't get it, but did get it again after a second restart.

Thoughts? Suggestions? This has happened before to others:

https://forums.macrumors.com/threads/1737877/
https://forums.macrumors.com/threads/1737749/

Meanwhile, https://www.sslshopper.com/ssl-checker.html#hostname=swscan.apple.com
indicates there are no problems.

Ghost in the machine?

NSA in the machine? /

 

[Alrescha]

If the time/date on your computer is invalid (or very inaccurate), this can sometimes cause the certificate validation process to fail.

A.

 

[MrElvey]

True. But, that's not the case here. My computer has the correct time/date.
e.g.

% date
Mon Sep 29 13:54:36 PDT 2014

Perhaps related: The App Store seems to be confused bout updating iMovie. It thinks it has installed 10.0.5, and yet it is also offering to install it. 10.0.5 iMovie is listed thrice: twice under Updates Installed in the Last 30 Days, and once under Update Available! I don't have iMovie 10 installed; I do have old copies of iMovie though.