Upgrade fails

Hi folks,

I am trying to upgrade BE2012 to 2015 but the upgrade fails with error:

And the summary.txt file contains:

Overall summary:
  Final result:                  Failed: see details below
  Exit code (Decimal):           -2067922409
  Exit facility code:            1214
  Exit error code:               535
  Exit message:                  One or more selected features for upgrade have failed the SID check. See the rules documentation at http://go.microsoft.com/fwlink/?LinkId=94001 for information on how to resolve.
  Start time:                    2015-12-07 17:45:18
  End time:                      2015-12-07 17:46:02
  Requested action:              Upgrade

I have checked the following article about SID issues: https://www.veritas.com/support/en_US/article.000021526#Top but first i cannot find the Powershell script and when i use the psgetsid method all i get is:

PS C:\Users\tcapacci\Desktop> .\PsGetsid.exe SQLServer2005MSSQLUser$NLGSWBAK01$BKUPEXEC

PsGetSid v1.44 - Translates SIDs to names and vice versa
Copyright (C) 1999-2008 Mark Russinovich
Sysinternals - www.sysinternals.com

Error querying account:
No mapping between account names and security IDs was done.