Since upgrading from Windows 7 to Windows 10 I can no longer access my mailbox from my exchange server or connect to my remote desktop at work.  In outlook I get error code 8, followed by a prompt to view certificate and continue or otherwise.  When I view certificate it is in date and I try and re-install but no matter what I try or where I install it does not work.

When I try and connect to the remote computer using remote desktop I get the error message that the identity of the remote computer cannot be identified and so it will not let me connect.

Both of these worked without fault when I was using Windows 7.  Am I missing something or need to change some security setting?

Seems like Windows is having trouble validating the certificates. Which in turn can be caused by several things, such as missing Root/chain certificates, firewall blocking connection to CRLs, etc.

As for Outlook, you can follow the instructions in this article to suppress the certificate warnings: https://support.microsoft.com/en-us/kb/2783881

But that's a workaround, and obviously will not apply to things like RDP, so you should focus on finding the root cause.

Is the computer that was upgraded your personal PC off of the network or a domain joined computer and you're using it remotely?  If it's a work computer and part of a domain, it may need to be unjoined from the domain and rejoined again.

It is my personal computer that I use to view my work emails via the exchange server. 

Hi,

According to your description, I understand you can't access your mailbox from the exchange server.

If your computer is part of a domain, please follow B0ndoo7's suggestion to unjoin from the domain and rejoin again.

In addiction, we can recreate a new outlook profile to test.

Regards,

David