Delegate error message when accepting meetings for owner
 

Hi,

I have a user that is accepting meetings on behalf of the calendar owner. Intermittently she is getting an error message "the function cannot be performed because the message has been changed" She insists she isn't changing the message and is simply accepting it. If she okays the message the meeting appears in the owners calendar as tentative, i assume this is because the meeting hasn't actually been accepted.

I have searched google and mostly find the answer is SP3 upgrade, however, we are on SP3 already.

Any ideas?