Greg

Thanks for your prompt response

The workbook in question is part of a set of near-identical workbooks, all of which reference an AddIn for common functions, so using the workbook without my own AddIn is not really an option, although there are others installed that I could remove. However, this problem has been reported on other machines that most likely don't have the same AddIns loaded as I do (apart from the one they depend on, of course)

There are three changes in my Excel configuration - My own addin, the Adobe AddIn for PDF conversion, and the virus scanner

I have some other issues that I am attempting to resolve with the installation of my AddIn, so perhaps I will put this on hold until I have fixed the AddIn installation and see if it is still a problem then

Cheer

Andy