For the most part the guide posted by Microsoft is very useful and can be found here:

The problem arises in the adding the thumb print step. The documentation doesn’t mention this but when you copy the thumb print out of certmgr.msc (Step found here: you can’t just paste it into the XML file. Doing so will result in the following error…

Error 104 The XML specification is not valid: 
The 'thumbprint' attribute is invalid - 
The value '******REMOVED*******' is invalid according to its datatype '<a href=""></a> ThumbprintType' - 
The Pattern constraint failed.

You may also enjoy that the Schema link above returns an error.


The issue is three fold, unfortunately the documentation only mentions two issues: all spaces must be removed and all characters must be converted to uppercase. The third problem is the string actually contains several hidden characters at the beginning. To fix this simply place your cursor after the first character and hit backspace till you erase the opening quotation mark then put the quotation mark and first character back in by typing them in.

I don’t even want to admit how long it took me to figure this out last night. I was not able to get it to display the characters either even when converting them between encoding types.

About Author

Siva Katir

Siva Katir

Programmer working at MGM Solutions in Bellingham Washington.