Unexpected Error with Distribution Lists

[Lynn]

I am trying to send a message using 4 distribution lists. Each list contains
about 100 contacts. When I click Send, I receive a message that an
unexpected error has occurred. Is there a limit to # of lists/contacts I can
use in a message?

 

[Brian Tillman]

I am trying to send a message using 4 distribution lists. Each list
contains about 100 contacts. When I click Send, I receive a message
that an unexpected error has occurred. Is there a limit to # of
lists/contacts I can use in a message?

Outlook doesn't contain such a limit, but clearly there are internal data
structures in any program whose sizes under the correct circumstances could
be exceeded. I don't know if that's what's happening to you because there's
not enough detail in your description to decide where you should look. The
general approaches apply: Help>Detect and Repair (or Office Diagnostics,
depending on your version), possible new mail profile, and a few others.