VBA Macro to find duplicates from multiple columns

Dear everyone

I have a workbook with multiple columns with differiating data. I would need to compare the values of Column A to every other column with data on it, and highlight duplicates. (Note, only column A should be used as a comparison value. So A should be compared with B C and D, but B should not be compared with C or D.

Attached example workbook.

Dummy1.xlsx

So this is what my start setup looks like.

User1 User2 User3 User4 User5
X1 X1 X5 X4 R2
Y2 Y2 R2 X3 Y2
Y3 Y3 Y4 Y1 Y9
X2 Y4 Y7 Y2 X1
X3 Y5 Y3 Y7
Y4 X2 X1
Y5 X2
X4 X4
X5
R2


And this is what it should look like after running the macro


User1 User2 User3 User4 User5
X1 X1 X5 X4 R2
Y2 Y2 R2 X3 Y2
Y3 Y3 Y4 Y1 Y9
X2 Y4 Y7 Y2 X1
X3 Y5 Y3 Y7
Y4 X2 X1
Y5 X2
X4 X4
X5
R2


The purpose of this macro is to find values from columns B - XX, that aren't found in column A.
As from this example, the values Y7 and Y9 were found.

In the data workbook we're using, there's around 70 columns of data.

Pl see the attached file with Macro.

See the attached file with changed Code.