After a quick bit of testing, it seems if the addin is marked Read Only you
can delete/over write it whilst Excel is open and accessing the addin.
I assume the user would not be exposed to the updated version until they
restarted Excel.
Setting Read Only can be done in Explorer or with GetAttr/SetAttr in code.

NickHK

"ben" wrote in message
oups.com...
Hi
I've read couple of threads regarding this issue but I am still a bit
confused.
Here is the problem
I have an add in that that is stored in a shared drive and which is
refereneced in a spreadsheet. Many users can use it at the same time
I don't want to ask the users to close down Excel before I can update
the add in.
I want to update(overwrite the addin) while it is in use by other users
(ie loaded into Excel via a workbook that reference this addin and not
open directly as a workbook). No one will open the add in directly as a
workbook (ie double clicking on it from Windows Explorer or from an
existing Excel using File/Open menu ).

What do I need to do ?
Make sure the .xla is always read only (attributes = R) ?
What sequence should I follow if changes in attributes is required ?
Do the changes in attribiutes have to be done programatically or can I
do that for Windows explorer ?
Making sure that it alway open through a workbook referencing the addin
?

Help much apreciated
B