Failed to remove index 'nUserID" in table [ECUser]

[mediamole]

Trying to do an increment upgrade on Actinic V9 site to 2013 and on import into V10 or even V11 get the following error message:

Failed to remove index 'nUserID" in table [ECUser] - fatal error. Reported error was:

Cannot find the table or constraint

I've come across this error before, just having a memory lapse of what it may be. I though might be because database was version 97 but that appears incorrect and now 2000

Anyone advise?

[peblaco]

There's some information about V9 database tables and keys which may help here.

[mediamole]

Thanks for the tip. Also discovered was because the site was still in Access V97