Invalid web-site certificates? Check the obvious first: is the time on your VM image correct?

So, I'm downloading the MQ Explorer support pack.

I run a Mac, and this only works on Linux or Windows, so I fire up my Windows 7 VM image to do the necessary.

Onto the web-site, sign in, choose download method and get a 'This site does not have a valid certificate!' error in Chrome. Worrying! There's no obvious  'override this' in Chrome, so I try Firefox.

Firefox gives the 'This connection is Untrusted' page with the usual 'get me out of here/I understand the risks' options.

Now for internal web-servers, I'd normally hit 'I understand' - but this is an external one - and it's ibm.com - it should be OK? But what if I've been Man-In-The-Middled somewhere? OK, it's my DSL-Fibre connection but better safe than sorry . .

Looking at the screen however, I see this:

The certificate is valid from 15/12/2015 (That's 15th December, if you're used to US date formats!)

"The current time is 08/12/2015 13:44" - er, not it's not! Today is the 16th January 2016 (16/01/2016). What's going on?

So I check the time on Windows in the VMWare - sure enough, it thinks it's still December. The Time Server sync hasn't fired yet or has glitched and I haven't used this VMWare for ages: Obviously since 8th December.

So, I resync the time and everything starts working! Yay!

But I never usually check the time on VMs - why would I? I assumed that the time-server sync is keeping me up to date. It usually syncs up OK, but obviously not often enough - or it can have an error with time.windows.com.

So TL;DR: When firing up a VM, check and sync the VM time to the time server, every time. Then check it against your watch - just to be sure!