objShell.Run MailTo populate vars

this will help Short answer: No. Javascript can not change the way external programs interpret link protocols.
Javascript can however populate the link destination with dynamic content, but it can’t get around the usual browser limits that follows.

wish helps you It's because google & yahoo expect the url to have query strings of "?to=" instead of "?mailto=" See this question for more details

this one helps. The Macs are processing the link correctly. Windows is incorrectly removing data and your editor is incorrectly encoding the data.
The mailto: URL scheme is defined by RFC 2368. It defines it as:

 mailtoURL  =  "mailto:" [ to ] [ headers ]
 to         =  #mailbox
 headers    =  "?" header *( "&" header )
 header     =  hname "=" hvalue
 hname      =  *urlc
 hvalue     =  *urlc

seems to work fine As @Noodles pointed out in the comments to your question you need to set the third parameter of the Run method (bWaitOnReturn) to True so that your VBScript waits for the external command to complete.
However, that alone doesn't suffice. You also need to run sqlcmd with the additional parameter -b to make it return a non-zero exit code in case of an error:

rc = objshell.Run("sqlcmd -b -U sa -P Password -i c:\temp\abc.sql", 1, True)
If rc <> 0 Then
    WriteLog "Error running SQL = " & rc
Else
    WriteLog "Successfully run SQL"
End If

it helps some times Below is my attempt at adding yes/no options to my objshell.popup, getting a type mismatch error, probably doing something wrong... , It's because the signature for the Popup method is actually:

WshShell.Popup(strText, [nSecondsToWait], [strTitle], [intType])

intresult = objshell.popup(myStr, , strtitle, inttype)