Error! Unknown Error! when upgrading

[alexander1974]

Dear sir or madam,

I want to upgrade my SMF forum. I copied all the files from the large upgrade over my 2.15 installation and when I start /upgrade.php I can login and start the first step but there I get the error:

Error!
Unknown Error!

It is the part:

Database Changes
Executing database changes
Please be patient - this may take some time on large forums. The time elapsed increments from the server to show progress is being made!
Executing: "Changing column names." (1 of 42)

!!Error!
Unknown Error!

What could be wrong with my installation? I already uploaded the upgrade again and changed templates to the standard SMF template but that didn't solve my problem.

Kind regards
Alex

[Illori]

what version are you upgrading to?

also we really dont recommend using 2.0 RC2 in production as you can run into bugs/issues. it is best to stick with SMF 2.0.17 until 2.1 goes "gold".