We are experiencing ArcGIS portal upgrade error with site administrator account creation.
We have upgraded ArcGIS 10.2.2 portal to ArcGIS 10.3 portal with default configuration ( no Active Directory connection and no other custom changes in old version)
Please see below screen. Please help
I don't know about upgrading from 10.2.x to 10.3, I was having the same error when installing 10.3 raw. When reviewing the log file referenced in the Error Message, there was a line that said to "delete everything in the arcgisportal folder" or something similar. I believe it was not seeing the database store or some such thing. Finding information in this log should be key to your problem. I don't remember what I did to get ours working, but believe I deleted the folder and reinstalled Portal. But find and check your log file first. Again, I do not know if deleting the folder would negatively affect your 10.2.2 Portal data.
I know this post is a little old, but thought I would reply with one solution we did.
Using Firebug I could see the error that came though and it was related to the "Data Store".
To solve this I had to upgrade the Managed Database to the current version (in our case is 10.3.1)
Once that was done it worked.