runtime error 1004 method save of object _workbook failed

My question is
I have a workbook which I save a copy each day and am now having some problems. I get the following error
once and a while.
"runtime error 1004 method save of object _workbook failed error 1004 method save of object _workbook failed" and it also get a "File locked" when I try to save
the file. I believe my problem might be in the following code:

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Would this code conflict if I have 2 copies of the same workbook up at the same time and try to run this code in one?
I seem to only get the error message when I have 2 copies of the same workbook open at once.