Alternatives to fixing issue with excel file not getting unlocked

Currently, after test runs I write to excel file for capturing test metrics.

It seems that at times Microsoft does not unlock the excel spreadsheet and the test hangs until I manually kill the excel process.

Are there any suggestions on how to fix this issue. This prevents us from running our tests overnight all the way through.

The only alternative I can come up with is to write it to a text file as a .csv file.

P.S. I am writing to excel as an ActiveXObject

Looking for other alternatives.

Thanks,

Jeff