Error when upgrading vb 3.8

[chikuru]

http://www.******.org/vB/install/upg...0b6.php?step=2

Database error in vBulletin 3.8.7:

Invalid SQL:
ALTER TABLE attachment ADD INDEX userid (userid);

MySQL Error   : Duplicate key name 'userid'
Error Number  : 1061
Request Date  : Friday, January 29th 2016 @ 05:31:00 PM
Error Date    : Friday, January 29th 2016 @ 05:31:00 PM
Script        : http://www.*******.org/vB/install/upgrade_300b6.php?step=2
Referrer      : 
IP Address    : ***.***.***.***
Username      : 
Classname     : vB_Database
MySQL Version : 5.5.47-cll

I tried droping userid and still geting same error

[Dave]

Have you tried dropping the index called userid? An index and column are 2 different things.

[chikuru]

Originally Posted by Dave

Have you tried dropping the index called userid? An index and column are 2 different things.

Whats the query of it?
Thanks Dave!

[Dave]

PHP Code:

ALTER TABLE attachment DROP INDEX userid; 


If you dropped the column userid, you may face some problems though. The userid column is a mandatory column for the attachment table.

[chikuru]

After running the query, im now getting this:

Database error in vBulletin 3.8.7:

Invalid SQL:
ALTER TABLE attachment ADD INDEX userid (userid);

MySQL Error   : Duplicate key name 'userid'
Error Number  : 1061
Request Date  : Friday, January 29th 2016 @ 06:07:40 PM
Error Date    : Friday, January 29th 2016 @ 06:07:40 PM
Script        : http://www.*********.org/vB/install/upgrade_300b6.php?step=2
Referrer      : 
IP Address    : 
Username      : 
Classname     : vB_Database
MySQL Version : 5.5.47-cll

[Paul M]

What are you upgrading from and to ? - because something is seriously wrong to be running (or trying to run) upgrade_300b6.php?step=2 on a 3.8.7 database.