Maybe cleaning your windows Temp folder would help.

Debra Dalgleish has a suggestion to this FAQ:
http://www.contextures.com/xlfaqApp.html#AlreadyOpen

Plodhia wrote:

My computer had to be rebooted when I had an Excel file open. After
rebooting, when I tried to open the file, it has the file is open for
editing and does not allow me to open the file in normal mode. How do I set
the file to be closed, so I can open it normally?

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Dave Peterson