problem with Range statement in With-End With loop

In the sub below the following code gives an error.

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The problem is definetely with this line, because if I specify the Range to Range("D:D") the sub is working.
What is wrong here?
I attached a test Excel sheet with the macro.

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Untested but basically in this context you would either need to use:

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or

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using the latter is obviously simpler - using the former it would generally be a good idea to assign the sheet object to a variable so you can use shorthand reference.

(in essence each range object used must be qualified against the parent sheet object - Sheets("z").Range("D:D") works because you have one range object - using Range(Cells,Cells) you have three)