You can use userport (I'm the author).
See
http://extensions.joomla.org/extensions/migration-a-conversion/users-import-a-export/5430
You can do this with two updates:
- First update
- Generate a csv list of users with an activation string
- Copy that locally
- Clear the activation string of those users
- Ensure no mails get sent
- Second update
- Re-use the first list
- Re-set the activation string
- Ensure mails get sent.
Of course, first try and test with one test account of yours.
On Wed, 16 May 2012 16:56:55 +0200, Fran M. <
francis...@gmail.com>
wrote: