InstallationException - why?

When trying to send a message to another user, sometimes we get:

InstallationException

Type is not supported. This indicates an error in your installation, most likely caused by an incomplete upgrade.

Any idea what can be the cause?  Of course we hit 'upgrade'  many times..

  • Seems only when a user is admin this issue is here. When we remove admin status from this user, he can send message,ok . When we make him admin again, he can not send message and gets error above... Strange!

  • Are you on a modest server?  Since it's inconsistent you might be running out of resources or hitting you SQL quota.

  • It happens on our test server: Elgg 1.7.4 on EC2 of Amazon.

    I am quite sure not quota related as it  very consistent to always fails to send admin message.  Then making this user a non-admin, it works fine. Even with all plugins, except the messages plugin, enabled, same result.

    Little frigthening...

    Hmm... thought I had an idea... on production we have 1.7.5 and we copied database from that to test server that still had 1.7.4. But upgrade a minute ago did not help...