>>Hi All,
>>
>>Using Excel automation I want to open an Excel Workbook if it is not already open. How to check for this?
>>
>>Thanks beforehand.
>
>AFAIK the simplest way to check is to open with low-level fopen function. However, there is a very tiny chance of having the file opened by someone while you're testing for this.

Also found this thread Re: How can I check if excel File is open before writing to Thread #812502 Message #812506