Mail merge from Word to Excel locks the excel document

Question

Previously, a friend of mine would run his business like this:
Open a client database (excel file), open N number of word docs that were mail merge docs to the excel file.  He could then make changes to the excel file and see those changes reflected in real time in the opened word mail merge documents.  He
could also save the excel document while the word docs were open without problem.
Now, changes to excel are not shown in word, and saving the excel doc while the word mail merge documents are open produces a sharing violation (winword has a handle on the excel file).
I've reproduced his problems.  We are both using Office 2010, and Windows 7.
I've tested turning off indexing on the files, and also tried disabling my anti virus. 
If I save the excel file as a 97-2003 file (.xls), then I don't have most of these issues.
Is there anyway to avoid the file lock when using the excel document as a 2010 xlsx?  Why would it work fine if I connect to an old document, but not work with the 2010 version?

Answer 1

I have a similar problem, which might be related. I use an Excel 2010 spreadsheet (.xlsx) as a data source to mail merge with document templates (.dotx) in Word 2010. I can save changes to the Excel spreadsheet without any problems until open a Word template
and try to use the Excel spreadsheet as the data source (Mailings -> Select Recipients -> Using Existing List). Two problems occur when I run that merge. First, any recent changes to the spreadsheet don't appear in the document templates. Second, Excel
throws error messages when I try to save the spreadsheet. Specifically:
1. Excel tells me that "Your changes could not be saved to '[FILENAME].xlsx' because of a sharing violation. Try saving to a different file."
2. When I click OK, it tries to save the spreadsheet to a randomly-named file without an extension, and tells me "The file you are trying to open, '53F11100' (or some other seemingly-random file name) is in a different format than specified by the file extension.
Verify that the file is not corrupted and is from a trusted source before opening the file. Do you want to open the file now?" Excel gives me a yes/no option, either requires me to resave the file under a different name.
At this point, I can only save the spreadsheet under a different file name unless I close out of MS Office 2010 entirely, make a duplicate of the spreadsheet using Windows, and begin using the new copy instead of the old. I'm using Windows Vista SP2, and don't
recall any specific action on my part prompting this change, but it began happening in the last few weeks. Any guidance would be a huge help.
Thanks in advance,
Prescott