What does it mean "You do not have exclusive access?"

[Gina Whipp]

Lois,

That means you and someone else are in the database while you are trying to
make design changes. Now, if it's only you then it closed badly the last
time you closed it and you need to delete the *.ldb file.

Should none of those options apply, please feel free to use the big white
space to provide more details.

 

[John W. Vinson]

It's considered polite to use the big textbox to post a question, not just the
subject. For example you could describe what you're doing to get the error.

It means what it says: that you're trying to use a database that somebody else
already has open. If you're the only one in the database you might have it
open twice.