Dave Goldman I disagree. My cert *is* in the machine store:
PS C:\Users\Administrator.SOMERVILLES> dir cert:\LocalMachine\My
PSParentPath: Microsoft.PowerShell.Security\Certificate::LocalMachine\My
Thumbprint Subject
---------- -------
D2FC8B18A0F25752979903E4F94F793D9985E1D5 CN=Azure, O="XXX, Inc.", L=McLean, S=Virginia, C=US
...but, running from LocalSystem...
Error launching PowerShell: rc = 1, stderr = New-ExoPSSession : No certificate found for the given CertificateThumbprint :D2FC8B18A0F25752979903E4F94F793D9985E1D5
At C:\Program Files\WindowsPowerShell\Modules\ExchangeOnlineManagement\2.0.3\ExchangeOnlineManagement.psm1:481 char:30
+ ... PSSession = New-ExoPSSession -ExchangeEnvironmentName $ExchangeEnviro ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [New-ExoPSSession], Exception
+ FullyQualifiedErrorId : System.Exception,Microsoft.Exchange.Management.ExoPowershellSnapin.NewExoPSSession