While Upgrading from DNN 4.9.4 to 5.6.2, I get 3 errors:
1. Executing Script: 05.01.00.SqlDataProvider (Column names in each table must be unique. Column name 'LastModifiedOnDate' in table 'dbo.Files' is specified more than once.)
2. Executing Script: 05.05.00.SqlDataProvider (Invalid column name 'CreatedByUserID'.
Invalid column name 'CreatedOnDate'.
Invalid column name 'LastModifiedByUserID'.
Invalid column name 'LastModifiedByUserID'.)
3. Executing Script: 05.06.02.SqlDataProvider (Invalid column name 'LastModifiedByUserID'.)
All other steps complete successfully.

My questions are:
1. How do I fix these errors?
2. This is a backup of a live website that I am trying to upgrade. Are there any preventive steps to be taken before I upgrade the live website, so that I don't see these errors then?

I have not verified whether the website works inspite of the above errors.

Thank you,
Apeksha

Hi Daniel,
Thank you very much for the suggestions. And apologies for not getting back to you earlier.
I just tried this today, as indicated on the page you quoted:
1. Upgrade from 4.9.4 to 4.9.5 -> Successful.
2. Upgrade from 4.9.5 to 5.4.4 -> 1 Error - Executing Script: 05.01.00.SqlDataProvider (Column names in each table must be unique. Column name 'LastModifiedOnDate' in table 'dbo.Files' is specified more than once.)

Since DNN said "Upgrade Successful", I clicked on the "Click here to access your portal" link and examined my website to find that the file manager is not working.

Thank You,
Apeksha