Finding duplicate names

[Gordon1963]

I have a worksheet and there are company names we shouldn’t process. I have an exceptional list with those company names, so if those names appear in my worksheet, highlight those companies. Here is a sample

Exception list. New List
Lee Company. Pace
Legacy. LCMH
Abc. LCMH
LCMH. Lee Company
Legal Sea

From the example, LCMH should be highlighted twice and Lee Company once. These two companies should also be highlighted on the exception list. There will be approximately 500 exception companies and thousands on the list group. I tried Conditional formatting and if a company appears in the second column more than once, it highlighted it once.

 

[Cubist]

There will be 2 conditional formatting formulas one for each column.
For column A, highlight the cells, and insert this formula into the conditional formatting rule.

=COUNTIF($B$2:$B$6,A2)>0

It is counting the value of A2 in column B (hence it needs to be locked). If the count is more than 0, meaning it exists, then highlight the cell. With relative reference, it will apply the rule to cells A3, A4,... and so on.

Similarly, for column B, highlight the cells, and insert.

=COUNTIF($A$2:$A$6,B2)>0

It's the same formula but the columns are swapped. It's now checking if B2 is in column A.